A dual mode temperature measurement method and system

Abstract

The application provides a dual-mode temperature measurement method and system, wherein the method comprises the following steps: calibrating the coefficients of a secondary resistance thermometer measurement mode in situ by using a primary noise thermometer measurement mode, compared with a periodic calibration mode, the embodiment is beneficial to improving the convenience and safety of the calibration of the secondary resistance thermometer measurement mode. After calibrating the secondary resistance thermometer measurement mode in situ by using the primary noise thermometer measurement mode, the ambient temperature of a sensor measurement resistor is monitored by using the secondary resistance thermometer measurement mode. Compared with directly using the primary noise thermometer measurement mode, the embodiment uses the secondary resistance thermometer measurement mode to improve the temperature measurement efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of temperature measurement, and in particular to a dual-mode temperature measurement method and system. BACKGROUND

[0002] In industrial production such as nuclear industry, metallurgy industry, aerospace industry, etc., it is a great challenge to realize high-precision and long-term reliable temperature measurement. The commonly used secondary resistance thermometers, such as thermocouple thermometer or platinum resistance thermometer, have non-negligible defects for long-term temperature monitoring: impurity pollution or material phase transition caused by extreme environment such as high temperature or strong radiation will cause the temperature measurement performance to drift, so they need to be calibrated regularly. Regularly taking back the thermocouple thermometer or platinum resistance thermometer to be calibrated will undoubtedly reduce the convenience in industrial production. Moreover, in the nuclear industrial production environment, the thermocouple thermometer or platinum resistance thermometer to be calibrated is easily affected by nuclear radiation, and if it is regularly taken back to be calibrated, it will affect the safety of the measurement personnel.

[0003] Unlike the above-mentioned secondary resistance thermometer, Johnson primary noise thermometer as a primary temperature measurement method can infer the thermodynamic temperature of the environment according to the thermal noise signal power of the resistance within a certain bandwidth. The Johnson primary noise thermometer does not need to be graduated, has the advantages of zero drift and calibration-free, and is one of the primary temperature measurement methods recommended by the International Measurement Committee for realizing Kelvin after the reform of the International System of Units. However, the relatively complex system structure, the characteristics of being easily affected by electromagnetic interference and the relatively low measurement efficiency make the primary noise thermometer not widely used in industrial production. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a dual-mode temperature measurement method and system, which calibrates the coefficients in the secondary resistance thermometer temperature measurement mode by using the primary noise thermometer temperature measurement mode, which is beneficial to improve the convenience and safety of calibrating the coefficients in the secondary resistance thermometer temperature measurement mode, and after calibrating the coefficients in the secondary resistance thermometer temperature measurement mode by using the primary noise thermometer temperature measurement mode, the temperature is measured by using the secondary resistance thermometer temperature measurement mode, which is beneficial to improve the temperature measurement efficiency.

[0005] In a first aspect, embodiments of the present application provide a dual-mode temperature measurement method, which is applied to a dual-mode temperature measurement system; the dual-mode temperature measurement system comprises a differential reference noise source, a coaxial switch group, a probe rod, a cross-correlation device and a direct-current resistance measurement unit; the probe rod comprises a sensor temperature measurement resistor; when the sensor temperature measurement resistor forms a closed loop with the differential reference noise source through the coaxial switch group and forms a closed loop with the cross-correlation device through the coaxial switch group, the dual-mode temperature measurement system is in a primary noise thermometer temperature measurement mode; when the sensor temperature measurement resistor forms a closed loop with the direct-current resistance measurement unit through the coaxial switch group, the dual-mode temperature measurement system is in a secondary resistance thermometer temperature measurement mode; the method comprises:

[0006] For each first environmental temperature at which the dual-mode temperature measurement system is located, the dual-mode temperature measurement system is controlled to be in the secondary resistance thermometer temperature measurement mode, and a first resistance value of the sensor temperature measurement resistor at the first environmental temperature is measured by the direct-current resistance measurement unit; and the dual-mode temperature measurement system is controlled to be in the primary noise thermometer temperature measurement mode, and a voltage division power of a reference noise voltage signal generated by the differential reference noise source on the sensor temperature measurement resistor and a power of thermal noise signals generated by the sensor temperature measurement resistor are collected by the cross-correlation device;

[0007] A second environmental temperature at which the sensor temperature measurement resistor is located is calculated by the cross-correlation device based on the voltage division power, the power of the thermal noise signals and the first resistance value;

[0008] After obtaining the second environmental temperature at which the sensor temperature measurement resistor is located and the first resistance value of the sensor temperature measurement resistor when the dual-mode temperature measurement system is respectively located at each first environmental temperature, a least square fitting is performed on each second environmental temperature and each first resistance value to obtain a numerical value of a coefficient used for measuring an environmental temperature of an environment at which the sensor temperature measurement resistor is located in the secondary resistance thermometer temperature measurement mode, so as to calibrate a historical numerical value of the coefficient by using the numerical value.

[0009] In combination with the first aspect, embodiments of the present application provide a first possible implementation manner of the first aspect, wherein the differential reference noise source comprises a first resistor, a differential reference voltage source and a second resistor connected in series; when the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode, a positive electrode of the differential reference voltage source is connected to a positive electrode of the coaxial switch group through the first resistor, and a negative electrode of the differential reference voltage source is connected to a negative electrode of the coaxial switch group through the second resistor;

[0010] The differential reference voltage source comprises a single-ended first arbitrary waveform generator and a first single-ended to differential amplifier connected in series; wherein the positive pole of the first single-ended to differential amplifier is connected to the first resistor, and the negative pole of the first single-ended to differential amplifier is connected to the second resistor.

[0011] Alternatively, the differential reference voltage source comprises a single-ended first analog-to-digital converter and a second single-ended to differential amplifier connected in series; wherein the positive pole of the second single-ended to differential amplifier is connected to the first resistor, and the negative pole of the second single-ended to differential amplifier is connected to the second resistor.

[0012] Alternatively, the differential reference voltage source comprises a single-ended second arbitrary waveform generator and a single-ended third arbitrary waveform generator connected in series; wherein the second arbitrary waveform generator is connected to the first resistor, and the third arbitrary waveform generator is connected to the second resistor.

[0013] With reference to the first possible implementation manner of the first aspect, the second possible implementation manner of the first aspect is provided in the embodiments of the present application, wherein the coaxial switch group comprises six single-ended coaxial switches, each of which comprises three pins, i.e., a first pin, a second pin and a third pin; wherein the positive pole of the sensor temperature measuring resistor is connected to the third pin of three single-ended coaxial switches through a lead line, and the negative pole of the sensor temperature measuring resistor is connected to the third pin of the other three single-ended coaxial switches through a lead line.

[0014] For one of the three single-ended coaxial switches connected to the positive pole of the sensor temperature measuring resistor, the first pin of the single-ended coaxial switch is connected to the first resistor through a lead line, and the second pin of the single-ended coaxial switch is connected to a suspended pin through a lead line; the first pins of the other two single-ended coaxial switches connected to the positive pole of the sensor temperature measuring resistor are connected to the positive pole of the cross-correlation device through lead lines, and the second pins of the other two single-ended coaxial switches are connected to the positive pole of the direct current resistance measuring unit through lead lines.

[0015] For one of the three single-ended coaxial switches connected to the negative pole of the sensor temperature measuring resistor, the first pin of the single-ended coaxial switch is connected to the second resistor through a lead line, and the second pin of the single-ended coaxial switch is connected to a suspended pin through a lead line; the first pins of the other two single-ended coaxial switches connected to the negative pole of the sensor temperature measuring resistor are connected to the negative pole of the cross-correlation device through lead lines, and the second pins of the other two single-ended coaxial switches are connected to the negative pole of the direct current resistance measuring unit through lead lines.

[0016] When the third pin of each single-ended coaxial switch is connected to the first pin of the respective single-ended coaxial switch through a lead, the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the third pin of each single-ended coaxial switch is connected to the second pin of the respective single-ended coaxial switch through a lead, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode;

[0017] or,

[0018] The coaxial switch group comprises three integrated differential switches; each of the differential switches comprises a first coaxial lead, a second coaxial lead and a third coaxial lead; wherein the outer layer of the first coaxial lead is a first metal conductor layer, the outer layer of the second coaxial lead is a second metal conductor layer, and the outer layer of the third coaxial lead is a third metal conductor layer; the positive pole of the sensor temperature measurement resistance is respectively connected to the core of the third coaxial lead in each of the differential switches; and the negative pole of the sensor temperature measurement resistance is respectively connected to the first metal conductor layer, the second metal conductor layer and the third metal conductor layer.

[0019] The core of the first coaxial lead in one of the differential switches is connected to the first resistance, and the first metal conductor layer of the first coaxial lead is connected to the second resistance; the core of the second coaxial lead in the differential switch is connected to a suspended pin, and the second metal conductor layer of the second coaxial lead is connected to a suspended pin.

[0020] For the other two differential switches, the positive pole of the cross-correlation device is connected to the core of the first coaxial lead in the two differential switches, and the negative pole is connected to the first metal conductor layer; the positive pole of the direct current resistance measurement unit is connected to the core of the second coaxial lead in the two differential switches, and the negative pole is connected to the second metal conductor layer of the second coaxial lead.

[0021] When the core of the third coaxial lead in each of the differential switches is connected to the core of the first coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the first metal conductor layer of the first coaxial lead, the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the core of the third coaxial lead in each of the differential switches is connected to the core of the second coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the second metal conductor layer of the second coaxial lead, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode.

[0022] With reference to the second possible implementation manner of the first aspect, the third possible implementation manner of the first aspect is provided in the embodiments of the present application, wherein the outer layer of the probe rod is a fourth metal conductor layer, and the probe rod is internally provided with the sensor temperature measuring resistor and one, two or three fourth coaxial leads; the sensor temperature measuring resistor and the fourth coaxial leads are separated from the fourth metal conductor layer by a first insulating layer inside the probe rod; an outer layer of each of the fourth coaxial leads is a fifth metal conductor layer, and an inner part of the fourth coaxial lead is provided with a core, which is separated from the fifth metal conductor layer by a second insulating layer inside the fourth coaxial lead;

[0023] When the probe rod is internally provided with one fourth coaxial lead, a positive electrode of the sensor temperature measuring resistor is connected to one end of the core of the fourth coaxial lead through a lead, and a negative electrode is connected to the fifth metal conductor layer of the fourth coaxial lead through a lead;

[0024] When the coaxial switch group comprises six single-end coaxial switches, the other end of the core of the fourth coaxial lead is connected to the third pin of three single-end coaxial switches connected to the positive electrode of the sensor temperature measuring resistor through three leads, and the fifth metal conductor layer in the fourth coaxial lead is connected to the third pin of three single-end coaxial switches connected to the negative electrode of the sensor temperature measuring resistor through three leads;

[0025] When the coaxial switch group comprises three integrated differential switches, the other end of the core of the fourth coaxial lead is connected to the core of each third coaxial lead through three leads, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of each third coaxial lead through three leads;

[0026] When the probe rod is internally provided with two fourth coaxial leads, a positive electrode of the sensor temperature measuring resistor is connected to one end of the core of each fourth coaxial lead through a lead, and a negative electrode is connected to the fifth metal conductor layer in each fourth coaxial lead through a lead;

[0027] When the coaxial switch group comprises six single-end coaxial switches, the other end of the core of one of the fourth coaxial leads is connected to the third pin of two of the single-end coaxial switches connected to the positive pole of the sensor thermistor through two lead connections, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third pin of the two single-end coaxial switches connected to the negative pole of the sensor thermistor through two lead connections; the other end of the core of the other of the fourth coaxial leads is connected to the third pin of the other of the single-end coaxial switches connected to the positive pole of the sensor thermistor through one lead connection, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third pin of the other of the single-end coaxial switches connected to the negative pole of the sensor thermistor through one lead connection;

[0028] When the coaxial switch group comprises three integrated differential switches, the other end of the core of one of the fourth coaxial leads is connected to the core of two of the third coaxial leads through two lead connections, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of the two third coaxial leads through two lead connections; the other end of the core of the other of the fourth coaxial leads is connected to the core of the other of the third coaxial leads through one lead connection, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of the other of the third coaxial leads through one lead connection;

[0029] When three of the fourth coaxial leads are arranged inside the probe rod, the positive pole of the sensor thermistor is connected to one end of the core of each of the fourth coaxial leads through a lead, and the negative pole is connected to the fifth metal conductor layer of each of the fourth coaxial leads through a lead;

[0030] When the coaxial switch group comprises six single-end coaxial switches, the core of each of the fourth coaxial leads is connected to the third pin of one of the single-end coaxial switches connected to the positive pole of the sensor thermistor in turn, and the fifth metal conductor layer of each of the fourth coaxial leads is connected to the third pin of one of the single-end coaxial switches connected to the negative pole of the sensor thermistor in turn;

[0031] When the coaxial switch group comprises three integrated differential switches, the core of each of the fourth coaxial leads is connected to the core of one of the third coaxial leads in turn, and the fifth metal conductor layer of each of the fourth coaxial leads is connected to the third metal conductor layer of one of the third coaxial leads in turn.

[0032] With reference to the first aspect, in a fourth possible implementation of the first aspect, the cross-correlation device comprises a first preamplifier, a first low-pass filter, a first buffer, a second analog-to-digital converter, a second preamplifier, a second low-pass filter, a second buffer, a third analog-to-digital converter, a data processing unit, and an editable logic gate array; the first preamplifier, the first low-pass filter, the first buffer, the second analog-to-digital converter, the second preamplifier, and the editable logic gate array are sequentially connected; the second preamplifier, the second low-pass filter, the second buffer, the third analog-to-digital converter, and the editable logic gate array are sequentially connected; the editable logic gate array is connected to the data processing unit and the coaxial switch group; the data processing unit is further connected to the direct current resistance measuring unit; in the primary noise thermometer temperature measurement mode, the coaxial switch group is connected to the first preamplifier and the second preamplifier, respectively.

[0033] With reference to the fourth possible implementation of the first aspect, in a fifth possible implementation of the first aspect, the control of the dual-mode temperature measurement system in the secondary resistance thermometer temperature measurement mode comprises measuring, by the direct current resistance measuring unit, a first resistance value of the sensor temperature measurement resistance at the first ambient temperature; and the control of the dual-mode temperature measurement system in the primary noise thermometer temperature measurement mode comprises acquiring, by the cross-correlation device, a voltage division power of a reference noise voltage signal generated by the differential reference noise source on the sensor temperature measurement resistance, and a thermal noise signal power generated by the sensor temperature measurement resistance.

[0034] The first switching of the coaxial switch group is controlled by the cross-correlation device, so that the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode; in the secondary resistance thermometer temperature measurement mode, the second resistance value of the sensor temperature measurement resistance at the first ambient temperature is measured by the direct current resistance measuring unit.

[0035] The second switching of the coaxial switch group is controlled by the cross-correlation device, so that the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; in the primary noise thermometer temperature measurement mode, the voltage division power of the reference noise voltage signal generated by the differential reference noise source on the sensor temperature measurement resistance is acquired by the cross-correlation device, and the thermal noise signal power generated by the sensor temperature measurement resistance is acquired.

[0036] The coaxial switch group is controlled by the cross-correlation device to perform the first switching, so that the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode, in which the third resistance value of the sensor temperature measurement resistor at the first ambient temperature is measured by the direct current resistance measurement unit;

[0037] The first resistance value is obtained by calculating the mean value of the second resistance value and the third resistance value by the cross-correlation device.

[0038] With reference to the first possible implementation manner of the first aspect, the present application provides a sixth possible implementation manner of the first aspect, and the second ambient temperature of the sensor temperature measurement resistor is calculated based on the divided voltage power, the power of the thermal noise signal and the first resistance value by the cross-correlation device.

[0039] The cross-correlation power spectrum is obtained by performing cross-correlation calculation on the divided voltage power and the power of the thermal noise signal by the cross-correlation device.

[0040] The power ratio spectrum between the thermal noise signal and the reference noise voltage signal is calculated according to the cross-correlation power spectrum.

[0041] The second ambient temperature of the sensor temperature measurement resistor is calculated based on the power ratio spectrum and the first resistance value.

[0042] With reference to the sixth possible implementation manner of the first aspect, the present application provides a seventh possible implementation manner of the first aspect, and the second ambient temperature of the sensor temperature measurement resistor is calculated by:

[0043] The second ambient temperature of the sensor temperature measurement resistor is calculated by the following formula:

[0044]

[0045] Wherein, T1 represents the second ambient temperature; V ref represents the amplitude of each frequency component of the reference noise voltage signal; R T1 represents the first resistance value; a0 is a fitting value obtained by least square fitting on the power ratio spectrum; L represents the frequency interval of each harmonic classification of the reference noise voltage signal in the frequency domain; R F1 is the sum of the resistances of the first resistor and the second resistor; k is the Boltzmann constant; Δf is the frequency resolution of the cross-correlation power spectrum; T F1 is the ambient temperature of the environment in which the first resistor and the second resistor are located.

[0046] With reference to the first aspect, the embodiments of the present application provide an eighth possible implementation manner of the first aspect, and the method further comprises:

[0047] controlling the dual-mode temperature measurement system to be in the secondary resistance thermometer temperature measurement mode, and measuring a fourth resistance value of the sensor temperature measurement resistance by the direct current resistance measurement unit in the secondary resistance thermometer temperature measurement mode;

[0048] calculating an ambient temperature of an environment in which the sensor temperature measurement resistance is located by the following formula:

[0049]

[0050] wherein R T2 is the fourth resistance value; R0 is a resistance value of the sensor temperature measurement resistance at 0°C; T2 is the ambient temperature of the environment in which the sensor temperature measurement resistance is located; and α and β are values of the coefficients obtained after the present calibration.

[0051] In the second aspect, the embodiments of the present application further provide a dual-mode temperature measurement system, which comprises a differential reference noise source, a coaxial switch group, a probe rod, a cross-correlation device and a direct current resistance measurement unit; the probe rod comprises a sensor temperature measurement resistance; when the sensor temperature measurement resistance forms a closed loop with the differential reference noise source through the coaxial switch group, and the sensor temperature measurement resistance forms a closed loop with the cross-correlation device through the coaxial switch group, the dual-mode temperature measurement system is in a primary noise thermometer temperature measurement mode; when the sensor temperature measurement resistance forms a closed loop with the direct current resistance measurement unit through the coaxial switch group, the dual-mode temperature measurement system is in a secondary resistance thermometer temperature measurement mode.

[0052] The cross-correlation device is configured to, for each first ambient temperature at which the dual-mode temperature measurement system is located, control the dual-mode temperature measurement system to be in the secondary resistance thermometer temperature measurement mode at the first ambient temperature.

[0053] The direct current resistance measurement unit is configured to measure a first resistance value of the sensor temperature measurement resistance at the first ambient temperature in the secondary resistance thermometer temperature measurement mode.

[0054] The cross-correlation device is further configured to control the dual-mode temperature measurement system to be in the primary noise thermometer temperature measurement mode, and collect a voltage division power of a reference noise voltage signal generated by the differential reference noise source on the sensor temperature measurement resistance, and a power of a thermal noise signal generated by the sensor temperature measurement resistance.

[0055] The cross-correlation device is further configured to calculate a second ambient temperature of an environment in which the sensor temperature measurement resistance is located based on the voltage division power, the power of the thermal noise signal and the first resistance value.

[0056] The cross-correlation device is further configured to, after obtaining the second ambient temperature of the sensor thermistor and the first resistance value of the sensor thermistor when the dual-mode temperature measurement system is respectively at each of the first ambient temperatures, perform a least square fitting on each of the second ambient temperatures and each of the first resistance values to obtain a value of a coefficient used for measuring an ambient temperature of an environment in which the sensor thermistor is located in the secondary resistance thermometer temperature measurement mode, so as to calibrate a historical value of the coefficient using the value.

[0057] The dual-mode temperature measurement method and system provided by the embodiments of the present application automatically calibrate the coefficient used for temperature measurement in the secondary resistance thermometer temperature measurement mode by using the primary noise thermometer temperature measurement mode, which is beneficial to improving the convenience and safety of the calibration of the coefficient in the secondary resistance thermometer temperature measurement mode compared with the calibration mode of periodically retrieving the secondary resistance thermometer. Meanwhile, after the calibration of the coefficient in the secondary resistance thermometer temperature measurement mode by using the primary noise thermometer temperature measurement mode, the use of the secondary resistance thermometer temperature measurement mode to measure the ambient temperature of the environment in which the sensor thermistor is located is beneficial to improving the temperature measurement efficiency compared with the temperature measurement mode using the primary noise thermometer temperature measurement mode.

[0058] In order to make the above objectives, characteristics and advantages of the present application more apparent, the following will describe a preferred embodiment in detail, and the accompanying drawings will be referred to, as follows. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation to the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0060] Figure 1 Fig. 1 shows a structure diagram of a dual-mode temperature measurement system provided by an embodiment of the present application;

[0061] Figure 2 Fig. 3 shows structure diagrams of three differential reference voltage sources provided by an embodiment of the present application;

[0062] Figure 3 Fig. 5 shows a structure diagram of a coaxial switch group provided by an embodiment of the present application;

[0063] Figure 4 Fig. 7 shows a structure diagram of another coaxial switch group provided by an embodiment of the present application;

[0064] Figure 5 Fig. 1 shows a structural schematic diagram of three probe rods provided by an embodiment of the present application;

[0065] Figure 6 Fig. 2 shows a structural schematic diagram of a sensor temperature measurement resistor provided by an embodiment of the present application;

[0066] Figure 7 Fig. 3 shows a flow chart of a dual-mode temperature measurement method provided by an embodiment of the present application;

[0067] Figure 8 Fig. 4 shows a schematic diagram of a reference noise voltage signal provided by an embodiment of the present application;

[0068] Figure 9 Fig. 5 shows a schematic diagram of a cross-correlation calculation of a divided voltage power and a thermal noise signal provided by an embodiment of the present application. DETAILED DESCRIPTION

[0069] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0070] It is considered that the calibration of the coefficients in the secondary resistance thermometer temperature measurement mode by means of periodic retrieval will reduce the convenience and safety in industrial production. Moreover, when temperature measurement is performed using the primary noise thermometer temperature measurement mode, the problem of low temperature measurement efficiency is prone to occur. Based on this, the embodiments of the present application provide a dual-mode temperature measurement method and system, which are described below by embodiments.

[0071] In order to facilitate the understanding of the embodiments, first, a dual-mode temperature measurement method disclosed by the embodiments of the present application is described in detail. The method is applied to a dual-mode temperature measurement system; as shown in Figure 1 The dual-mode temperature measurement system includes a differential reference noise source, a coaxial switch group, a probe rod, a cross-correlation device and a direct current resistance measurement unit; the probe rod contains a sensor temperature measurement resistor R T ; wherein the sensor temperature measurement resistor R T forms a closed loop with the differential reference noise source through the coaxial switch group, and the sensor temperature measurement resistor RT When the coaxial switch group and the interconnecting device form a closed loop, the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the sensor temperature measuring resistor forms a closed loop with the DC resistance measuring unit through the coaxial switch group, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode.

[0072] In this embodiment, the sensor temperature measuring resistor R T This is a thermocouple resistor or a platinum resistance thermometer. For example... Figure 1 As shown, when the switch in the coaxial switch group is switched to "1", the sensor temperature measuring resistor R... T A closed loop is formed by the coaxial switch assembly and the differential reference noise source, while the sensor's temperature measuring resistor R... T A closed loop is formed by the coaxial switch group and the cross-correlation device. At this time, the dual-mode temperature measurement system is in primary noise thermometer measurement mode. When the switch in the coaxial switch group is switched to "2", the sensor's temperature sensing resistance R... T The coaxial switch group and the DC resistance measurement unit form a closed loop. At this time, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode.

[0073] In one possible implementation, such as Figure 1 As shown, the differential reference noise source includes a first resistor R1, a differential reference voltage source, and a second resistor R2 connected in series. When the dual-mode temperature measurement system is in primary noise thermometer measurement mode, the positive terminal of the differential reference voltage source is connected to the positive terminal of the coaxial switch group through the first resistor R1, and the negative terminal of the differential reference voltage source is connected to the negative terminal of the coaxial switch group through the second resistor R2.

[0074] like Figure 2 As shown, this embodiment provides three implementation methods for a differential reference voltage source:

[0075] In the first implementation of the differential reference voltage source: the differential reference voltage source includes a first arbitrary waveform generator and a first single-ended to differential amplifier connected in series; wherein, the positive terminal of the first single-ended to differential amplifier is connected to a first resistor R1, and the negative terminal of the first single-ended to differential amplifier is connected to a second resistor R2.

[0076] In the second implementation of the differential reference voltage source: the differential reference voltage source includes a first single-ended analog-to-digital converter (DAC) and a second single-ended to differential amplifier connected in series; wherein, the positive terminal of the second single-ended to differential amplifier is connected to a first resistor R1, and the negative terminal of the second single-ended to differential amplifier is connected to a second resistor R2.

[0077] In the third implementation of the differential reference voltage source: the differential reference voltage source includes a single-ended second arbitrary waveform generator and a single-ended third arbitrary waveform generator connected in series; wherein, the second arbitrary waveform generator is connected to the first resistor R1, and the third arbitrary waveform generator is connected to the second resistor R2.

[0078] in, Figure 1 The differential reference voltage source in the differential reference noise source is Figure 2 The third implementation method of differential reference voltage source.

[0079] In one possible implementation, the coaxial switch assembly is structured as follows: Figure 3 and Figure 4 As shown, there are two implementation methods:

[0080] in, Figure 1 The structure used in the coaxial switch assembly is as follows: Figure 3 The structure shown is as follows: Figure 1 and Figure 3 As shown, in the first implementation of the coaxial switch group: the coaxial switch group includes six single-ended coaxial switches ( Figure 3 In order from left to right, the switches are the first, second, third, fourth, fifth, and sixth single-ended coaxial switches. Each single-ended coaxial switch contains three pins: pin 1, pin 2, and pin 3. Figure 3 The text only labels the first and third pins of the first single-ended coaxial switch, and the second and third pins of the sixth single-ended coaxial switch.

[0081] Among them, the sensor temperature measuring resistor R T The positive terminal is connected to the lead (e.g.) Figure 3 (As shown by the thick lines) Connect to the third pin of each of the three single-ended coaxial switches (first single-ended coaxial switch, second single-ended coaxial switch, and third single-ended coaxial switch), and the sensor temperature measuring resistor R T The negative terminal is connected to the lead (e.g. Figure 3 The thin line (as shown) is connected to the third pin of the other three single-ended coaxial switches (the fourth single-ended coaxial switch, the fifth single-ended coaxial switch, and the sixth single-ended coaxial switch).

[0082] Regarding the sensor temperature sensing resistor R T One of the three single-ended coaxial switches connected to the positive terminal (the first single-ended coaxial switch) is connected to a first resistor R1 via a lead, and the second pin of the single-ended coaxial switch is connected to a floating pin via a lead, which is connected to the temperature sensing resistor R of the sensor. TThe first pin of the other two single-ended coaxial switches (the second single-ended coaxial switch and the third single-ended coaxial switch) of the three single-ended coaxial switches connected to the positive pole of the cross-correlation device is connected to the positive pole of the direct-current resistance measuring unit through a lead wire;

[0083] The third pin of one single-ended coaxial switch (the fourth single-ended coaxial switch) of the three single-ended coaxial switches connected to the negative pole of the sensor temperature measuring resistor R T is connected to the first pin of the single-ended coaxial switch through a lead wire, and the second pin of the single-ended coaxial switch is connected to a floating pin. The first pin of the other two single-ended coaxial switches (the fifth single-ended coaxial switch and the sixth single-ended coaxial switch) of the three single-ended coaxial switches connected to the negative pole of the sensor temperature measuring resistor R T is connected to the negative pole of the cross-correlation device through a lead wire, and the second pin of the other two single-ended coaxial switches (the fifth single-ended coaxial switch and the sixth single-ended coaxial switch) is connected to the negative pole of the direct-current resistance measuring unit through a lead wire.

[0084] When the third pin in each single-ended coaxial switch is connected to the first pin in the respective single-ended coaxial switch through a lead wire (as shown in FIGS. 1 and 2, each single-ended coaxial switch is switched to “1”), the dual-mode temperature measurement system is in a primary noise thermometer temperature measurement mode. Figure 3 When the third pin in each single-ended coaxial switch is connected to the second pin in the respective single-ended coaxial switch through a lead wire (as shown in FIGS. 3 and 4, each single-ended coaxial switch is switched to “2”), the dual-mode temperature measurement system is in a secondary resistance thermometer temperature measurement mode. Figure 1 Figure 3 As shown in FIG. 5, in an implementation manner of a second coaxial switch group: the coaxial switch group includes three integrated differential switches (in order from left to right, the first differential switch, the second differential switch, and the third differential switch in FIG. 5); each differential switch includes a first coaxial lead wire, a second coaxial lead wire, and a third coaxial lead wire (in FIG. 5, only the first coaxial lead wire and the third coaxial lead wire of the first differential switch and the second coaxial lead wire of the third differential switch are labeled by words). Figure 1 The outer layer of the first coaxial lead wire is a first metal conductor layer, the outer layer of the second coaxial lead wire is a second metal conductor layer, and the outer layer of the third coaxial lead wire is a third metal conductor layer; the positive pole of the sensor temperature measuring resistor R T is connected to the core of the third coaxial lead wire in each differential switch; and the negative pole of the sensor temperature measuring resistor is connected to the first metal conductor layer, the second metal conductor layer, and the third metal conductor layer, respectively.

[0085] As shown in FIG. 5, in an implementation manner of a second coaxial switch group: the coaxial switch group includes three integrated differential switches (in order from left to right, the first differential switch, the second differential switch, and the third differential switch in FIG. 5); each differential switch includes a first coaxial lead wire, a second coaxial lead wire, and a third coaxial lead wire (in FIG. 5, only the first coaxial lead wire and the third coaxial lead wire of the first differential switch and the second coaxial lead wire of the third differential switch are labeled by words). Figure 3 The outer layer of the first coaxial lead wire is a first metal conductor layer, the outer layer of the second coaxial lead wire is a second metal conductor layer, and the outer layer of the third coaxial lead wire is a third metal conductor layer; the positive pole of the sensor temperature measuring resistor R T is connected to the core of the third coaxial lead wire in each differential switch; and the negative pole of the sensor temperature measuring resistor is connected to the first metal conductor layer, the second metal conductor layer, and the third metal conductor layer, respectively. Figure 4 Figure 4 As shown in FIG. 5, in an implementation manner of a second coaxial switch group: the coaxial switch group includes three integrated differential switches (in order from left to right, the first differential switch, the second differential switch, and the third differential switch in FIG. 5); each differential switch includes a first coaxial lead wire, a second coaxial lead wire, and a third coaxial lead wire (in FIG. 5, only the first coaxial lead wire and the third coaxial lead wire of the first differential switch and the second coaxial lead wire of the third differential switch are labeled by words).

[0086] In one of the differential switches (first differential switches), the core of the first coaxial lead is connected to the first resistor R1, and the first metal conductor layer of the first coaxial lead is connected to the second resistor R2; the core of the second coaxial lead in the differential switch (first differential switch) is connected to the floating foot, and the second metal conductor layer of the second coaxial lead is connected to the floating foot.

[0087] For the other two differential switches (the second differential switch and the third differential switch), the positive terminal of the cross-correlation device is connected to the core of the first coaxial lead in the two differential switches, and the negative terminal of the cross-correlation device is connected to the first metal conductor layer in the two differential switches; the positive terminal of the DC resistance measurement unit is connected to the core of the second coaxial lead in the two differential switches, and the negative terminal of the DC resistance measurement unit is connected to the second metal conductor layer of the second coaxial lead in the two differential switches.

[0088] When the core of the third coaxial lead in each differential switch is connected to the core of the first coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the first metal conductor layer of the first coaxial lead (i.e.) Figure 4 In the process of switching each differential switch to "1", the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the core of the third coaxial lead in each differential switch is connected to the core of the second coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the second metal conductor layer of the second coaxial lead (i.e. Figure 4 When each differential switch is switched to "2", the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode.

[0089] In one possible implementation, such as Figure 4 As shown, the probe rod has three structural implementations, among which the outer layer of the probe rod is a fourth metal conductor layer ( Figure 5 (Only the location of each layer is marked in the first implementation method). The probe rod is equipped with a sensor temperature measuring resistor R. T And one, two, or three fourth coaxial leads; sensor temperature measuring resistor R T The fourth coaxial lead is separated from the fourth metal conductor layer by the first insulation layer inside the probe rod; the outer layer of each fourth coaxial lead is the fifth metal conductor layer, and the fourth coaxial lead has a wire core inside, which is separated from the fifth metal conductor layer by the second insulation layer inside the fourth coaxial lead;

[0090] In the first implementation of the probe rod, namely Figure 5 The first probe in the sequence from top to bottom has a fourth coaxial lead inside, and the sensor's temperature measuring resistor R... T The positive terminal is connected to one end of the core of the fourth coaxial lead via a lead wire, and the sensor temperature measuring resistor R TThe fourth coaxial lead's fifth metal conductor layer is connected by three leads to the third pin of the three single-ended coaxial switches connected to the positive pole of the sensor thermistor resistor R

[0091] When the coaxial switch group comprises six single-ended coaxial switches as shown in Figure 5 , the other end of the fourth coaxial lead's core is connected by three leads to the third pin of the three single-ended coaxial switches connected to the positive pole of the sensor thermistor resistor R T , and the fourth coaxial lead's fifth metal conductor layer is connected by three leads to the third pin of the three single-ended coaxial switches connected to the negative pole of the sensor thermistor resistor R

[0092] When the coaxial switch group comprises three integrated differential switches as shown in Figure 3 , the other end of the fourth coaxial lead's core is connected by three leads to the core of each third coaxial lead (each third coaxial lead refers to the third coaxial lead in the first differential switch, the second differential switch and the third differential switch in Figure 4 ), and the fourth coaxial lead's fifth metal conductor layer is connected by three leads to the third metal conductor layer of each third coaxial lead.

[0093] In the second implementation of the probe rod, i.e. Figure 4 , the second probe rod in the order from top to bottom in , the probe rod is internally provided with two fourth coaxial leads, the positive pole of the sensor thermistor resistor R T is connected by leads to one end of the core of each fourth coaxial lead, and the negative pole of the sensor thermistor resistor R T is connected by leads to the fifth metal conductor layer in each fourth coaxial lead.

[0094] Figure 5 When the coaxial switch group comprises six single-ended coaxial switches as shown in Figure 3 , the other end of the core of one of the fourth coaxial leads is connected by two leads to the third pin of the two single-ended coaxial switches connected to the positive pole of the sensor thermistor resistor R T , and the fourth coaxial lead's fifth metal conductor layer is connected by two leads to the third pin of the two single-ended coaxial switches connected to the negative pole of the sensor thermistor resistor R T ; the other end of the core of the other fourth coaxial lead is connected by one lead to the third pin of the other single-ended coaxial switch connected to the positive pole of the sensor thermistor resistor R T Figure 3 Figure 3 ​​The third pin of the third single-ended coaxial switch (in the fourth coaxial lead) is connected to the sensor temperature measuring resistor R via a lead. T Another single-ended coaxial switch connected to the negative terminal ( Figure 3 The third pin of the sixth single-ended coaxial switch in the circuit.

[0095] When the coaxial switch group includes, for example Figure 3 When the three integrated differential switches are shown, the other end of the core in one of the fourth coaxial leads is connected to two of the third coaxial leads via two separate leads. Figure 4 The core of the third coaxial lead in the first differential switch and the third coaxial lead in the second differential switch, the fifth metal conductor layer of the fourth coaxial lead is connected to the two third coaxial leads respectively by two leads. Figure 4 The third metal conductor layer of the third coaxial lead in the first differential switch and the third coaxial lead in the second differential switch; the other end of the core of another fourth coaxial lead is connected to another third coaxial lead via a lead. Figure 4 The core of the third coaxial lead in the third differential switch, the fifth metal conductor layer of the fourth coaxial lead is connected to another third coaxial lead via a lead. Figure 4 The third metal conductor layer of the third coaxial lead in the third differential switch.

[0096] In the third implementation of the probe rod, namely Figure 4 The third probe in the sequence from top to bottom has three fourth coaxial leads inside, and the sensor's temperature measuring resistor R... T The positive terminal is connected to one end of the core of each fourth coaxial lead via a lead wire, and the sensor temperature measuring resistor R T The negative terminal is connected to the fifth metal conductor layer of each fourth coaxial lead via leads.

[0097] When the coaxial switch group includes, for example Figure 5 When the six single-ended coaxial switches shown are used, the core of each fourth coaxial lead is sequentially connected to a sensor temperature measuring resistor R. T The third pin of a single-ended coaxial switch connected to the positive terminal (e.g., Figure 3 The core connection of the first fourth coaxial lead in the third probe. Figure 5 The third pin of the first single-ended coaxial switch is connected to the core of the second and fourth coaxial leads. Figure 3 The third pin of the second single-ended coaxial switch, the core of the third fourth coaxial lead is connected to... Figure 3 The third pin of the third single-ended coaxial switch in the middle, the fifth metal conductor layer of each fourth coaxial lead is sequentially connected to a sensor temperature measuring resistor R. Tthe third pin of the single-ended coaxial switch whose negative pole is connected to the negative pole of the first single-ended coaxial switch (e.g. Figure 3 the fifth metal conductor layer of the first fourth coaxial lead wire is connected to Figure 5 the third pin of the fourth single-ended coaxial switch in the first differential switch, the fifth metal conductor layer of the second fourth coaxial lead wire is connected to Figure 3 the third pin of the fifth single-ended coaxial switch, the fifth metal conductor layer of the third fourth coaxial lead wire is connected to Figure 3 the third pin of the sixth single-ended coaxial switch).

[0098] When the coaxial switch group includes three integrated differential switches as shown in Figure 3 the core of the first fourth coaxial lead wire is connected to the core of a third coaxial lead wire in turn (e.g. Figure 4 the core of the first fourth coaxial lead wire is connected to the core of a third coaxial lead wire in turn (e.g. Figure 5 the core of the third coaxial lead wire in the first differential switch, the core of the second fourth coaxial lead wire is connected to Figure 4 the core of the third coaxial lead wire in the second differential switch, the core of the third fourth coaxial lead wire is connected to Figure 4 the core of the third coaxial lead wire in the third differential switch), the fifth metal conductor layer of each fourth coaxial lead wire is connected to the third metal conductor layer of a third coaxial lead wire in turn (e.g. Figure 4 the fifth metal conductor layer of the first fourth coaxial lead wire is connected to the third metal conductor layer of a third coaxial lead wire in turn (e.g. Figure 5 the third metal conductor layer of the third coaxial lead wire in the first differential switch, the fifth metal conductor layer of the second fourth coaxial lead wire is connected to Figure 4 the third metal conductor layer of the third coaxial lead wire in the second differential switch, the fifth metal conductor layer of the first fourth coaxial lead wire is connected to Figure 4 the third metal conductor layer of the third coaxial lead wire in the third differential switch).

[0099] In a possible implementation, as shown in Figure 4As shown, the cross-correlation device includes a first preamplifier, a first low-pass filter, a first buffer, a second analog-to-digital converter (ADC), a second preamplifier, a second low-pass filter (ADC), a second buffer, a third ADC, a data processing unit (e.g., a PC or MCU), and a field-programmable gate array (FPGA). The first preamplifier, first low-pass filter, first buffer, second ADC, second preamplifier, and FPGA are connected sequentially. The second preamplifier, second low-pass filter, second buffer, third ADC, and FPGA are also connected sequentially. The FPGA connects the data processing unit (PC or MCU) and a coaxial switch group. The data processing unit (PC or MCU) is also connected to a DC resistance measurement unit. In the primary noise thermometer temperature measurement mode, the coaxial switch group connects to the first and second preamplifiers respectively.

[0100] In one possible implementation, such as Figure 1 As shown, the sensor's temperature sensing resistor R T It can be a single resistor or a resistor consisting of two resistors connected in series.

[0101] The temperature measurement method in this embodiment is mainly divided into two stages. The first stage is to calibrate the coefficient in the secondary resistance thermometer temperature measurement mode; the second stage is to use the calibrated coefficient to measure the temperature in the secondary resistance thermometer temperature measurement mode.

[0102] In the first phase, such as Figure 6 As shown, the process includes the following steps S101-S103:

[0103] S101: For each first ambient temperature at which the dual-mode temperature measurement system is located, at that first ambient temperature, the dual-mode temperature measurement system is controlled to be in the secondary resistance thermometer temperature measurement mode, and the first resistance value of the sensor temperature measuring resistor is measured at that first ambient temperature through the DC resistance measurement unit; and the dual-mode temperature measurement system is controlled to be in the primary noise thermometer temperature measurement mode, and the power of the reference noise voltage signal generated by the differential reference noise source is collected through the cross-correlation device, which is the voltage division power of the reference noise voltage signal generated by the differential reference noise source on the sensor temperature measuring resistor, and the power of the thermal noise signal generated by the sensor temperature measuring resistor.

[0104] S102: Calculate the second ambient temperature of the sensor's temperature measuring resistor based on the voltage divider power, the power of the thermal noise signal, and the first resistance value using cross-correlation devices.

[0105] S103: After obtaining the second ambient temperature at which the sensor temperature measuring resistor is located and the first resistance value of the sensor temperature measuring resistor when the dual-mode temperature measuring system is at each first ambient temperature, respectively, performing least square fitting on each second ambient temperature and each first resistance value to obtain a value of a coefficient used for measuring the ambient temperature of the environment in which the sensor temperature measuring resistor is located in the secondary resistance thermometer temperature measuring mode, so as to calibrate the historical value of the coefficient using the value.

[0106] In this embodiment, i constant first ambient temperatures are set in advance, and at each first ambient temperature, steps S101-S102 are performed once.

[0107] In a possible implementation, when step S101 is performed, the following steps can be specifically performed:

[0108] S1011: The coaxial switch group is controlled by the cross-correlation device to perform first switching, so that the dual-mode temperature measuring system is in the secondary resistance thermometer temperature measuring mode, and in the secondary resistance thermometer temperature measuring mode, the second resistance value of the sensor temperature measuring resistor at the first ambient temperature is measured by the direct current resistance measuring unit.

[0109] S1012: The coaxial switch group is controlled by the cross-correlation device to perform second switching, so that the dual-mode temperature measuring system is in the primary noise thermometer temperature measuring mode, and in the primary noise thermometer temperature measuring mode, the power of the voltage signal of the reference noise generated by the differential reference noise source on the sensor temperature measuring resistor and the power of the thermal noise signal generated by the sensor temperature measuring resistor are collected by the cross-correlation device.

[0110] S1013: The coaxial switch group is controlled by the cross-correlation device to perform first switching, so that the dual-mode temperature measuring system is in the secondary resistance thermometer temperature measuring mode, and in the secondary resistance thermometer temperature measuring mode, the third resistance value of the sensor temperature measuring resistor at the first ambient temperature is measured by the direct current resistance measuring unit.

[0111] S1014: The cross-correlation device calculates the mean value of the second resistance value and the third resistance value to obtain the first resistance value.

[0112] In step S1011, for each first ambient temperature, when the dual-mode temperature measuring system is at the first ambient temperature, as shown in Figure 7 、 Figure 1 and Figure 3 , the field programmable gate array (FPGA) sends a first switching instruction to the coaxial switch group, and the coaxial switch group performs first switching according to the first switching instruction. The first switching is to switch the coaxial switch group to "2", at this time, the dual-mode temperature measuring system is in the secondary resistance thermometer temperature measuring mode, and in the secondary resistance thermometer temperature measuring mode, the second resistance value of the sensor temperature measuring resistor R Ta second resistance value at the first ambient temperature.

[0113] In step S1012, the editable logic gate array (FPGA) sends a second switching instruction to the coaxial switch group, and the coaxial switch group performs a second switching according to the second switching instruction, the second switching being switching the coaxial switch group to "1", at this time, the dual-mode temperature measurement system is in a primary noise thermometer temperature measurement mode, in the primary noise thermometer temperature measurement mode, the power of the reference noise voltage signal generated by the differential reference noise source is divided by the power of the thermal noise signal on the sensor temperature measurement resistor R T . T .

[0114] The reference noise voltage signal generated by the differential reference noise source is composed of a series of sine waves superimposed, and in the frequency domain, it is expressed as a comb-shaped signal with equal intervals, as shown in Figure 4 .

[0115] In step S1013, the editable logic gate array (FPGA) sends a first switching instruction to the coaxial switch group, and the coaxial switch group performs a first switching according to the first switching instruction, the first switching being switching the coaxial switch group to "2", at this time, the dual-mode temperature measurement system is in a secondary resistance thermometer temperature measurement mode, in the secondary resistance thermometer temperature measurement mode, the sensor temperature measurement resistor R T is measured again by the direct current resistance measurement unit. a third resistance value at the first ambient temperature.

[0116] In step S1014, the mean value of the second resistance value and the third resistance value is calculated by the data processing unit (PC or MCU) to obtain the second ambient temperature of the sensor temperature measurement resistor R T a first resistance value at the first ambient temperature.

[0117] In one possible implementation, when step S102 is performed, the following steps can be specifically performed:

[0118] S1021: The correlation between the divided power and the power of the thermal noise signal is calculated by the correlation device to obtain a correlation power spectrum;

[0119] S1022: According to the correlation power spectrum, a power ratio spectrum between the thermal noise signal and the reference noise voltage signal is calculated;

[0120] S1023: Based on the power ratio spectrum and the first resistance value, the second ambient temperature of the sensor temperature measurement resistor is calculated.

[0121] In steps S1021-S1023, the cross-correlation calculation of the power of the voltage divider and the thermal noise signal is performed by the data processing unit (PC or MCU) to obtain the cross-correlation power spectrum; based on the cross-correlation power spectrum, the power ratio spectrum between the thermal noise signal and the reference noise voltage signal is calculated.

[0122] In step S1021, as Figure 8 As shown, when the sampling frequency of the reference noise voltage signal and the thermal noise signal in the time domain is f... S The single acquisition time is 2t. The time-domain data of the acquired reference noise voltage signal and thermal noise signal are divided into two parts: 0~t and t~2t. Assume the amplified voltage divider signal is V. S (t), the amplifier background noise in the two time periods are V respectively. n1 (t) and V n2 If V(t), then the measured time-domain signals V1(t) and V2(t) are respectively:

[0123] V1(t)=V s (t)+V n1 (t)

[0124] V2(t)=V S (t)+V n2 (t)

[0125] Performing Discrete Fourier Transforms on the time-domain signals V1(t) and V2(t) respectively yields a bandwidth of f. S / 2. Spectrum values ​​V1(w) and V2(w) with a resolution of 1 / t. According to Wiener-Khinchin's theorem, the cross-correlation calculation and cross-correlation power spectral density are Fourier transform pairs. After performing discrete Fourier transforms on V1(t) and V2(t), multiplying V1(w) by the conjugate of V2(w) yields the cross-correlation power spectral density:

[0126]

[0127] The cross-correlation power spectral density is integrated over a resolution of f Hz to obtain the cross-correlation power spectrum.

[0128] In step S1022, if the reference noise voltage signal consists of N sine waves with a frequency interval of L Hz, then its voltage-divided signal also appears as N multi-frequency signals with an interval of L Hz in the cross-correlation power spectrum. The power values ​​of the discrete thermal noise signals adjacent to the Mth voltage-divided signal in the cross-correlation power spectrum are added together to obtain a thermal noise power value. The power ratio r between the Mth voltage-divided signal and its adjacent thermal noise powers is:

[0129]

[0130] Where m and M are frequency index values; Pm and P M respectively represent the discrete thermal noise power value and the power ratio of the divided voltage signal. Finally, N discrete power ratio values r M are obtained, each point has the following relationship with the frequency f:

[0131] r M = a0+ a2f 2 + a4f 4 +... + a 2i f 2i

[0132] The N discrete power ratio values r M are least square fitted to obtain the constant a0 when the frequency f is 0.

[0133] In step S1023, the second ambient temperature where the sensor temperature measuring resistor R T is located is calculated by the following formula:

[0134]

[0135] Wherein, T1 represents the second ambient temperature; V ref represents the amplitude of each frequency component of the reference noise voltage signal; R T1 represents the first resistance value; a0 is the fitting value obtained by least square fitting the power ratio spectrum; L represents the frequency interval of each harmonic classification of the reference noise voltage signal in the frequency domain; R F1 is the sum of the resistances of the first resistor and the second resistor; k is the Boltzmann constant; Δf is the frequency resolution of the cross-correlation power spectrum; T F1 is the ambient temperature of the environment where the first resistor and the second resistor are located.

[0136] When performing step S103, when measuring the ambient temperature of the environment where the sensor temperature measuring resistor is located in the secondary resistance thermometer temperature measurement mode, two coefficients need to be used, which need to be calibrated regularly to make the temperature measurement in the secondary resistance thermometer temperature measurement mode more accurate. In this embodiment, by least square fitting each of the second ambient temperatures and each of the first resistance values, the numerical value of the coefficient used when measuring the ambient temperature of the environment where the sensor temperature measuring resistor is located in the secondary resistance thermometer temperature measurement mode is obtained, and then the newly obtained numerical value is used to calibrate the old historical numerical value of the coefficient. Wherein, the historical numerical value refers to the numerical value of the coefficient before this calibration, and the new numerical value of the coefficient obtained in this calibration process is used as the numerical value of the coefficient after this calibration.

[0137] In the second stage, after obtaining the new numerical value of the coefficient through this calibration, the temperature can be measured in the following way:

[0138] S1041: controlling the dual-mode temperature measurement system to be in a secondary resistance thermometer temperature measurement mode, in the secondary resistance thermometer temperature measurement mode, measuring a fourth resistance value of the sensor temperature measurement resistance by the direct current resistance measurement unit;

[0139] S1042: calculating an ambient temperature of an environment in which the sensor temperature measurement resistance is located by the following formula:

[0140]

[0141] wherein R T2 is the fourth resistance value; R0 is a resistance value of the sensor temperature measurement resistance at 0°C; T2 is the ambient temperature of the environment in which the sensor temperature measurement resistance is located; and a and b are values of the coefficients obtained after the present calibration.

[0142] In step S1041, the field programmable gate array (FPGA) sends a first switching instruction to the coaxial switch group, and the coaxial switch group performs a first switching according to the first switching instruction. The first switching is switching the coaxial switch group to "2", at this time, the dual-mode temperature measurement system is in a secondary resistance thermometer temperature measurement mode, in the secondary resistance thermometer temperature measurement mode, the direct current resistance measurement unit measures the fourth resistance value of the sensor temperature measurement resistance R T .

[0143] In step S1042, based on the fourth resistance value and the new values of the coefficients obtained after the present calibration, the ambient temperature of the environment in which the sensor temperature measurement resistance is located is calculated.

[0144] Based on the same technical concept, the present application also provides a dual-mode temperature measurement system, as shown in Figure 9 Figure 1 , the system comprises a differential reference noise source, a coaxial switch group, a probe rod, a cross-correlation device and a direct current resistance measurement unit; the probe rod contains a sensor temperature measurement resistance; wherein when the sensor temperature measurement resistance forms a closed loop with the differential reference noise source through the coaxial switch group, and the sensor temperature measurement resistance forms a closed loop with the cross-correlation device through the coaxial switch group, the dual-mode temperature measurement system is in a primary noise thermometer temperature measurement mode; when the sensor temperature measurement resistance forms a closed loop with the direct current resistance measurement unit through the coaxial switch group, the dual-mode temperature measurement system is in a secondary resistance thermometer temperature measurement mode;

[0145] The cross-correlation device is configured to control the dual-mode temperature measurement system to be in the secondary resistance thermometer temperature measurement mode at each first ambient temperature at which the dual-mode temperature measurement system is located.

[0146] The direct current resistance measurement unit is configured to measure a first resistance value of the sensor temperature measurement resistance at the first ambient temperature in the secondary resistance thermometer temperature measurement mode.

[0147] The cross-correlation device is further configured to control the dual-mode temperature measurement system to be in the primary noise thermometer temperature measurement mode, to collect a voltage division power of a reference noise voltage signal generated by the differential reference noise source on the sensor temperature measurement resistor, and a thermal noise signal power generated by the sensor temperature measurement resistor;

[0148] The cross-correlation device is further configured to calculate a second ambient temperature of the sensor temperature measurement resistor based on the voltage division power, the thermal noise signal power, and the first resistance value.

[0149] The cross-correlation device is further configured to, after obtaining the second ambient temperature of the sensor temperature measurement resistor and the first resistance value of the sensor temperature measurement resistor when the dual-mode temperature measurement system is respectively in each of the first ambient temperatures, perform a least square fitting on each of the second ambient temperatures and each of the first resistance values to obtain a numerical value of a coefficient used for measuring an ambient temperature of an ambient environment of the sensor temperature measurement resistor in the secondary resistance thermometer temperature measurement mode, so as to calibrate a historical numerical value of the coefficient using the numerical value.

[0150] Optionally, the differential reference noise source comprises a first resistor, a differential reference voltage source, and a second resistor connected in series.

[0151] The differential reference voltage source comprises a single-ended first arbitrary waveform generator and a first single-ended to differential amplifier connected in series.

[0152] Alternatively, the differential reference voltage source comprises a single-ended first analog-to-digital converter and a second single-ended to differential amplifier connected in series.

[0153] Alternatively, the differential reference voltage source comprises a single-ended second arbitrary waveform generator and a single-ended third arbitrary waveform generator connected in series.

[0154] Optionally, the coaxial switch group comprises six single-ended coaxial switches, each of which comprises three pins, namely a first pin, a second pin and a third pin; wherein the positive pole of the sensor temperature resistance is connected to the third pin of three single-ended coaxial switches through a lead, and the negative pole of the sensor temperature resistance is connected to the third pin of the other three single-ended coaxial switches through a lead;

[0155] For one of the three single-ended coaxial switches connected to the positive pole of the sensor temperature resistance, the first pin of the single-ended coaxial switch is connected to the first resistance through a lead, and the second pin of the single-ended coaxial switch is connected to a suspended pin. The first pins of the other two single-ended coaxial switches connected to the positive pole of the sensor temperature resistance are connected to the positive pole of the cross-correlation device through a lead, and the second pins of the other two single-ended coaxial switches are connected to the positive pole of the DC resistance measurement unit through a lead;

[0156] For one of the three single-ended coaxial switches connected to the negative pole of the sensor temperature resistance, the first pin of the single-ended coaxial switch is connected to the second resistance through a lead, and the second pin of the single-ended coaxial switch is connected to a suspended pin. The first pins of the other two single-ended coaxial switches connected to the negative pole of the sensor temperature resistance are connected to the negative pole of the cross-correlation device through a lead, and the second pins of the other two single-ended coaxial switches are connected to the negative pole of the DC resistance measurement unit through a lead;

[0157] When the third pin in each single-ended coaxial switch is connected to the first pin in the respective single-ended coaxial switch through a lead, the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the third pin in each single-ended coaxial switch is connected to the second pin in the respective single-ended coaxial switch through a lead, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode;

[0158] Or,

[0159] The coaxial switch group comprises three integrated differential switches; each of the differential switches comprises a first coaxial lead, a second coaxial lead and a third coaxial lead; wherein the outer layer of the first coaxial lead is a first metal conductor layer, the outer layer of the second coaxial lead is a second metal conductor layer, and the outer layer of the third coaxial lead is a third metal conductor layer; the positive pole of the sensor temperature resistance is connected to the core of the third coaxial lead in each differential switch; and the negative pole of the sensor temperature resistance is connected to the first metal conductor layer, the second metal conductor layer and the third metal conductor layer, respectively;

[0160] the core of the first coaxial lead of one of the differential switches is connected to the first resistor, and the first metal conductor layer of the first coaxial lead is connected to the second resistor; the core of the second coaxial lead of the differential switch is connected to a suspended pin, and the second metal conductor layer of the second coaxial lead is connected to a suspended pin;

[0161] for the other two differential switches, the positive electrode of the cross-correlation device is connected to the core of the first coaxial lead of the two differential switches, and the negative electrode is connected to the first metal conductor layer; the positive electrode of the direct current resistance measuring unit is connected to the core of the second coaxial lead of the two differential switches, and the negative electrode is connected to the second metal conductor layer of the second coaxial lead of the two differential switches;

[0162] when the core of the third coaxial lead of each differential switch is connected to the core of the first coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the first metal conductor layer of the first coaxial lead, the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the core of the third coaxial lead of each differential switch is connected to the core of the second coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the second metal conductor layer of the second coaxial lead, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode.

[0163] Optionally, the outer layer of the probe rod is a fourth metal conductor layer, and the probe rod is internally provided with the sensor temperature measurement resistor and one, two or three fourth coaxial leads; the sensor temperature measurement resistor and the fourth coaxial leads are separated from the fourth metal conductor layer by a first insulating layer inside the probe rod; the outer layer of each fourth coaxial lead is a fifth metal conductor layer, and the fourth coaxial lead is internally provided with a core which is separated from the fifth metal conductor layer by a second insulating layer inside the fourth coaxial lead;

[0164] when the probe rod is internally provided with one fourth coaxial lead, the positive electrode of the sensor temperature measurement resistor is connected to one end of the core of the fourth coaxial lead through a lead, and the negative electrode is connected to the fifth metal conductor layer of the fourth coaxial lead through a lead;

[0165] when the coaxial switch group includes six single-ended coaxial switches, the other end of the core of the fourth coaxial lead is connected to the third pin of three single-ended coaxial switches connected to the positive electrode of the sensor temperature measurement resistor through three leads, and the fifth metal conductor layer in the fourth coaxial lead is connected to the third pin of three single-ended coaxial switches connected to the negative electrode of the sensor temperature measurement resistor through three leads;

[0166] When the coaxial switch group comprises three integrated differential switches, the other end of the core of the fourth coaxial lead is connected to the core of each of the third coaxial leads through three leads, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of each of the third coaxial leads through three leads;

[0167] When two fourth coaxial leads are arranged inside the probe rod, the positive pole of the sensor temperature measuring resistor is connected to one end of the core of each of the fourth coaxial leads through leads, and the negative pole is connected to the fifth metal conductor layer of each of the fourth coaxial leads through leads;

[0168] When the coaxial switch group comprises six single-end coaxial switches, the other end of the core of one of the fourth coaxial leads is connected to the third pin of two of the single-end coaxial switches connected to the positive pole of the sensor temperature measuring resistor through two leads, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third pin of the two single-end coaxial switches connected to the negative pole of the sensor temperature measuring resistor through two leads; the other end of the core of the other fourth coaxial lead is connected to the third pin of the other single-end coaxial switch connected to the positive pole of the sensor temperature measuring resistor through one lead, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third pin of the other single-end coaxial switch connected to the negative pole of the sensor temperature measuring resistor through one lead;

[0169] When the coaxial switch group comprises three integrated differential switches, the other end of the core of one of the fourth coaxial leads is connected to the core of two of the third coaxial leads through two leads, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of the two third coaxial leads through two leads; the other end of the core of the other fourth coaxial lead is connected to the core of the other third coaxial lead through one lead, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of the other third coaxial lead through one lead;

[0170] When three fourth coaxial leads are arranged inside the probe rod, the positive pole of the sensor temperature measuring resistor is connected to one end of the core of each of the fourth coaxial leads through leads, and the negative pole is connected to the fifth metal conductor layer of each of the fourth coaxial leads through leads;

[0171] When the coaxial switch group comprises six single-end coaxial switches, the core of each of the fourth coaxial leads is connected to the third pin of one of the single-end coaxial switches connected to the positive pole of the sensor temperature measuring resistor in turn, and the fifth metal conductor layer of each of the fourth coaxial leads is connected to the third pin of one of the single-end coaxial switches connected to the negative pole of the sensor temperature measuring resistor in turn.

[0172] When the coaxial switch group comprises three integrated differential switches, the core of each fourth coaxial lead is connected to the core of a third coaxial lead in turn, and the fifth metal conductor layer of each fourth coaxial lead is connected to the third metal conductor layer of a third coaxial lead in turn.

[0173] Optionally, the cross-correlation device comprises a first preamplifier, a first low-pass filter, a first buffer, a second analog-to-digital converter, a second preamplifier, a second low-pass filter, a second buffer, a third analog-to-digital converter, a data processing unit, and an editable logic gate array; the first preamplifier, the first low-pass filter, the first buffer, the second analog-to-digital converter, the second preamplifier, and the editable logic gate array are sequentially connected; the second preamplifier, the second low-pass filter, the second buffer, the third analog-to-digital converter, and the editable logic gate array are sequentially connected; the editable logic gate array is connected to the data processing unit and the coaxial switch group; the data processing unit is further connected to the direct-current resistance measuring unit; in the primary noise thermometer temperature measurement mode, the coaxial switch group is connected to the first preamplifier and the second preamplifier, respectively.

[0174] Optionally, the cross-correlation device is configured to, for each first environmental temperature at which the dual-mode temperature measurement system is located, when the dual-mode temperature measurement system is controlled to be in the secondary resistance thermometer temperature measurement mode at the first environmental temperature, specifically configured to:

[0175] control the coaxial switch group to perform first switching, so that the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode;

[0176] the direct-current resistance measuring unit is configured to, when measuring a first resistance value of the sensor temperature measurement resistance at the first environmental temperature in the secondary resistance thermometer temperature measurement mode, specifically configured to:

[0177] measure a second resistance value of the sensor temperature measurement resistance at the first environmental temperature in the secondary resistance thermometer temperature measurement mode;

[0178] the cross-correlation device is configured to, when controlling the dual-mode temperature measurement system to be in the primary noise thermometer temperature measurement mode, collect the voltage division power of the power of the reference noise voltage signal generated by the differential reference noise source on the sensor temperature measurement resistance, and the power of the thermal noise signal generated by the sensor temperature measurement resistance, specifically configured to:

[0179] controlling the coaxial switch group to perform the second switching, so that the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode, in which the cross-correlation device collects a voltage division power of a reference noise voltage signal generated by the differential reference noise source on the sensor temperature measurement resistor, and a thermal noise signal power generated by the sensor temperature measurement resistor;

[0180] The cross-correlation device is further configured to, for each first ambient temperature at which the dual-mode temperature measurement system is controlled to be in the secondary resistance thermometer temperature measurement mode:

[0181] controlling the coaxial switch group to perform the first switching, so that the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode;

[0182] The direct current resistance measurement unit is further configured to, when measuring the first resistance value of the sensor temperature measurement resistor at the first ambient temperature in the secondary resistance thermometer temperature measurement mode:

[0183] measuring, in the secondary resistance thermometer temperature measurement mode, a third resistance value of the sensor temperature measurement resistor at the first ambient temperature by the direct current resistance measurement unit;

[0184] The cross-correlation device is further configured to calculate a mean value of the second resistance value and the third resistance value to obtain the first resistance value.

[0185] Optionally, the cross-correlation device is configured to, when calculating a second ambient temperature at which the sensor temperature measurement resistor is located based on the voltage division power, the thermal noise signal power, and the first resistance value, specifically configured to:

[0186] correlating the voltage division power and the thermal noise signal power by the cross-correlation device to obtain a cross-correlation power spectrum;

[0187] calculating a power ratio spectrum between the thermal noise signal and the reference noise voltage signal according to the cross-correlation power spectrum;

[0188] calculating the second ambient temperature at which the sensor temperature measurement resistor is located based on the power ratio spectrum and the first resistance value.

[0189] Optionally, the cross-correlation device is configured to, when calculating the second ambient temperature at which the sensor temperature measurement resistor is located based on the power ratio spectrum and the first resistance value, specifically configured to:

[0190] calculating the second ambient temperature at which the sensor temperature measurement resistor is located by the following formula:

[0191]

[0192] wherein T1 represents the second ambient temperature; V ref represents the amplitude of each frequency component of the reference noise voltage signal; R T1 represents the first resistance value; a0 is a fitting value obtained by least square fitting the power ratio spectrum; L represents the frequency interval of each harmonic classification of the reference noise voltage signal in the frequency domain; R F1 is the sum of the resistances of the first resistance and the second resistance; k is the Boltzmann constant; Δf is the frequency resolution of the cross-correlation power spectrum; T F1 is the ambient temperature of the environment in which the first resistance and the second resistance are located.

[0193] Optionally, the cross-correlation device is further configured to:

[0194] control the dual-mode temperature measurement system to be in the secondary resistance thermometer temperature measurement mode, and measure a fourth resistance value of the sensor temperature measurement resistance by the direct current resistance measurement unit in the secondary resistance thermometer temperature measurement mode;

[0195] calculate the ambient temperature of the environment in which the sensor temperature measurement resistance is located by the following formula:

[0196]

[0197] wherein R T2 is the fourth resistance value; R0 is the resistance value of the sensor temperature measurement resistance at 0℃; T2 is the ambient temperature of the environment in which the sensor temperature measurement resistance is located; and α and β are the numerical values of the coefficients obtained after the present calibration.

[0198] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system described above can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0199] In several embodiments provided in the present application, it should be understood that the disclosed system and method can be implemented in other ways. The device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units or components shown or discussed can be indirect coupling or communication connection through some communication interfaces, devices or units, and can be electrical, mechanical or other forms.

[0200] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e. may be located in one place, or may be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0201] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0202] If the functions are realized in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer readable storage medium executable by a processor. Based on this understanding, the technical solutions of the present application or the part of the present application that essentially contributes to the prior art or the part of the technical solutions can be embodied in the form of a software product, which is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0203] Finally, it should be noted that: the above-described embodiments are only specific embodiments of the present application, used to illustrate the technical solutions of the present application, and not to limit them, the protection scope of the present application is not limited thereto, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand: any skilled person in the art within the technical scope disclosed by the present application, they can still modify or easily think of changes to the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and all should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A dual-mode temperature measurement method, characterized in that, The method is applied to a dual-mode temperature measurement system; the dual-mode temperature measurement system includes a differential reference noise source, a coaxial switch group, a probe, a cross-correlation device, and a DC resistance measurement unit; the probe includes a sensor temperature-sensing resistor; wherein, when the sensor temperature-sensing resistor forms a closed loop with the differential reference noise source through the coaxial switch group, and when the sensor temperature-sensing resistor forms a closed loop with the cross-correlation device through the coaxial switch group, the dual-mode temperature measurement system is in primary noise thermometer temperature measurement mode; when the sensor temperature-sensing resistor forms a closed loop with the DC resistance measurement unit through the coaxial switch group, the dual-mode temperature measurement system is in secondary resistance thermometer temperature measurement mode; the method includes: For each first ambient temperature at which the dual-mode temperature measurement system is located, at that first ambient temperature, the dual-mode temperature measurement system is controlled to be in the secondary resistance thermometer temperature measurement mode, and the first resistance value of the sensor temperature measuring resistor is measured by the DC resistance measurement unit at that first ambient temperature; and the dual-mode temperature measurement system is controlled to be in the primary noise thermometer temperature measurement mode, and the power of the reference noise voltage signal generated by the differential reference noise source is collected by the cross-correlation device, which is the voltage division power of the reference noise voltage signal generated by the differential reference noise source on the sensor temperature measuring resistor, and the power of the thermal noise signal generated by the sensor temperature measuring resistor; The second ambient temperature of the sensor's temperature-measuring resistor is calculated using the cross-correlation device based on the voltage divider power, the power of the thermal noise signal, and the first resistance value. After obtaining the second ambient temperature of the sensor temperature measuring resistor and the first resistance value of the sensor temperature measuring resistor when the dual-mode temperature measurement system is at each of the first ambient temperatures, the least squares method is used to fit each second ambient temperature and each first resistance value to obtain the value of the coefficient used to measure the ambient temperature of the environment where the sensor temperature measuring resistor is located in the secondary resistance thermometer temperature measurement mode, so as to use the value to calibrate the historical value of the coefficient. The differential reference noise source includes a first resistor, a differential reference voltage source, and a second resistor connected in series. When the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode, the positive terminal of the differential reference voltage source is connected to the positive terminal of the coaxial switch group through the first resistor, and the negative terminal of the differential reference voltage source is connected to the negative terminal of the coaxial switch group through the second resistor. The differential reference voltage source includes a first arbitrary waveform generator and a first single-ended to differential amplifier connected in series; wherein, the positive terminal of the first single-ended to differential amplifier is connected to the first resistor, and the negative terminal of the first single-ended to differential amplifier is connected to the second resistor; Alternatively, the differential reference voltage source includes a first analog-to-digital converter and a second single-ended to differential amplifier connected in series; wherein the positive terminal of the second single-ended to differential amplifier is connected to the first resistor, and the negative terminal of the second single-ended to differential amplifier is connected to the second resistor; Alternatively, the differential reference voltage source includes a second arbitrary waveform generator and a third arbitrary waveform generator connected in series; wherein the second arbitrary waveform generator is connected to the first resistor, and the third arbitrary waveform generator is connected to the second resistor; The coaxial switch group includes six single-ended coaxial switches, each of which has three pins: a first pin, a second pin, and a third pin. The positive terminal of the temperature-sensing resistor is connected to the third pin of three of the single-ended coaxial switches via leads, and the negative terminal of the temperature-sensing resistor is connected to the third pin of the other three single-ended coaxial switches via leads. For one of the three single-ended coaxial switches connected to the positive terminal of the sensor temperature measuring resistor, the first pin of the single-ended coaxial switch is connected to the first resistor via a lead, and the second pin of the single-ended coaxial switch is connected to a floating pin via a lead. The first pins of the other two of the three single-ended coaxial switches connected to the positive terminal of the sensor temperature measuring resistor are connected to the positive terminal of the cross-correlation device via leads, and the second pins of the other two single-ended coaxial switches are connected to the positive terminal of the DC resistance measuring unit via leads. For one of the three single-ended coaxial switches connected to the negative terminal of the sensor temperature measuring resistor, the first pin of the single-ended coaxial switch is connected to the second resistor via a lead, and the second pin of the single-ended coaxial switch is connected to a floating pin via a lead. The first pins of the other two of the three single-ended coaxial switches connected to the negative terminal of the sensor temperature measuring resistor are connected to the negative terminal of the cross-correlation device via leads, and the second pins of the other two single-ended coaxial switches are connected to the negative terminal of the DC resistance measuring unit via leads. When the third pin of each of the single-ended coaxial switches is connected to the first pin of its respective single-ended coaxial switch via a lead wire, the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the third pin of each of the single-ended coaxial switches is connected to the second pin of its respective single-ended coaxial switch via a lead wire, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode. or, The coaxial switch group includes three integrated differential switches; each differential switch includes a first coaxial lead, a second coaxial lead, and a third coaxial lead; wherein the outer layer of the first coaxial lead is a first metal conductor layer, the outer layer of the second coaxial lead is a second metal conductor layer, and the outer layer of the third coaxial lead is a third metal conductor layer; the positive terminal of the sensor temperature measuring resistor is connected to the core of the third coaxial lead in each differential switch; the negative terminal of the sensor temperature measuring resistor is connected to the first metal conductor layer, the second metal conductor layer, and the third metal conductor layer. In one of the differential switches, the core of the first coaxial lead is connected to the first resistor, and the first metal conductor layer of the first coaxial lead is connected to the second resistor; the core of the second coaxial lead in the differential switch is connected to the floating leg, and the second metal conductor layer of the second coaxial lead is connected to the floating leg. For the other two differential switches, the positive terminal of the cross-correlation device is connected to the core of the first coaxial lead in the two differential switches, and the negative terminal is connected to the first metal conductor layer in the two differential switches; the positive terminal of the DC resistance measuring unit is connected to the core of the second coaxial lead in the two differential switches, and the negative terminal is connected to the second metal conductor layer of the second coaxial lead in the two differential switches. When the core of the third coaxial lead in each of the differential switches is connected to the core of the first coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the first metal conductor layer of the first coaxial lead, the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the core of the third coaxial lead in each of the differential switches is connected to the core of the second coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the second metal conductor layer of the second coaxial lead, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode. The outer layer of the probe rod is a fourth metal conductor layer. Inside the probe rod, there is a temperature-measuring resistor for the sensor and one, two, or three fourth coaxial leads. The temperature-measuring resistor for the sensor and the fourth coaxial leads are separated from the fourth metal conductor layer by a first insulating layer inside the probe rod. The outer layer of each fourth coaxial lead is a fifth metal conductor layer. Inside the fourth coaxial lead, there is a wire core, which is separated from the fifth metal conductor layer by a second insulating layer inside the fourth coaxial lead. When the probe rod is provided with a fourth coaxial lead, the positive terminal of the sensor temperature measuring resistor is connected to one end of the core of the fourth coaxial lead through the lead, and the negative terminal is connected to the fifth metal conductor layer of the fourth coaxial lead through the lead. When the coaxial switch group includes six single-ended coaxial switches, the other end of the core of the fourth coaxial lead is connected to the third pin of the three single-ended coaxial switches that are connected to the positive terminal of the sensor temperature measuring resistor through three leads, and the fifth metal conductor layer in the fourth coaxial lead is connected to the third pin of the three single-ended coaxial switches that are connected to the negative terminal of the sensor temperature measuring resistor through three leads. When the coaxial switch group includes three integrated differential switches, the other end of the core of the fourth coaxial lead is connected to the core of each of the third coaxial leads through three leads respectively, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of each of the third coaxial leads through three leads respectively. When the probe is provided with two fourth coaxial leads, the positive terminal of the sensor temperature measuring resistor is connected to one end of the core of each fourth coaxial lead through the lead, and the negative terminal is connected to the fifth metal conductor layer in each fourth coaxial lead through the lead. When the coaxial switch group includes six single-ended coaxial switches, one end of the core of the fourth coaxial lead is connected via two leads to the third pin of two single-ended coaxial switches connected to the positive terminal of the temperature-sensing resistor. The fifth metal conductor layer of the fourth coaxial lead is connected via two leads to the third pin of two single-ended coaxial switches connected to the negative terminal of the temperature-sensing resistor. The other end of the core of the fourth coaxial lead is connected via one lead to the third pin of another single-ended coaxial switch connected to the positive terminal of the temperature-sensing resistor. The fifth metal conductor layer of the fourth coaxial lead is connected via one lead to the third pin of another single-ended coaxial switch connected to the negative terminal of the temperature-sensing resistor. When the coaxial switch group includes three integrated differential switches, the other end of the core of one of the fourth coaxial leads is connected to the cores of two of the third coaxial leads respectively through two leads, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of the two third coaxial leads respectively through two leads; the other end of the core of another fourth coaxial lead is connected to the core of another third coaxial lead through one lead, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of the other third coaxial lead through one lead; When the probe is equipped with three fourth coaxial leads, the positive terminal of the sensor temperature measuring resistor is connected to one end of the core of each fourth coaxial lead through the lead, and the negative terminal is connected to the fifth metal conductor layer of each fourth coaxial lead through the lead. When the coaxial switch group includes six single-ended coaxial switches, the core of each fourth coaxial lead is sequentially connected to the third pin of the single-ended coaxial switch that is connected to the positive terminal of the sensor temperature measuring resistor, and the fifth metal conductor layer of each fourth coaxial lead is sequentially connected to the third pin of the single-ended coaxial switch that is connected to the negative terminal of the sensor temperature measuring resistor. When the coaxial switch group includes three integrated differential switches, the core of each fourth coaxial lead is sequentially connected to the core of a third coaxial lead, and the fifth metal conductor layer of each fourth coaxial lead is sequentially connected to the third metal conductor layer of a third coaxial lead.

2. The method according to claim 1, characterized in that, The cross-correlation device includes a first preamplifier, a first low-pass filter, a first buffer, a second analog-to-digital converter, a second preamplifier, a second low-pass filter, a second buffer, a third analog-to-digital converter, a data processing unit, and a programmable gate array; wherein, the first preamplifier, the first low-pass filter, the first buffer, the second analog-to-digital converter, the second preamplifier, and the programmable gate array are connected sequentially; the second preamplifier, the second low-pass filter, the second buffer, the third analog-to-digital converter, and the programmable gate array are connected sequentially; the programmable gate array is connected to the data processing unit and the coaxial switch group; the data processing unit is also connected to the DC resistance measurement unit; in the primary noise thermometer temperature measurement mode, the coaxial switch group is connected to the first preamplifier and the second preamplifier respectively.

3. The method according to claim 2, characterized in that, The control of the dual-mode temperature measurement system to be in the secondary resistance thermometer temperature measurement mode, measuring the first resistance value of the sensor temperature-sensing resistor at the first ambient temperature through the DC resistance measurement unit; and the control of the dual-mode temperature measurement system to be in the primary noise thermometer temperature measurement mode, acquiring the power of the reference noise voltage signal generated by the differential reference noise source across the sensor temperature-sensing resistor and the power of the thermal noise signal generated by the sensor temperature-sensing resistor through the cross-correlation device, including: The coaxial switch group is controlled by the cross-correlation device to perform a first switch so that the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode. In the secondary resistance thermometer temperature measurement mode, the second resistance value of the sensor temperature measuring resistor is measured by the DC resistance measuring unit at the first ambient temperature. The coaxial switch group is controlled by the cross-correlation device to perform a second switching so that the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode. In the primary noise thermometer temperature measurement mode, the cross-correlation device collects the power of the reference noise voltage signal generated by the differential reference noise source, the voltage division power on the sensor temperature measuring resistor, and the power of the thermal noise signal generated by the sensor temperature measuring resistor. The coaxial switch group is controlled by the cross-correlation device to perform the first switching, so that the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode. In the secondary resistance thermometer temperature measurement mode, the third resistance value of the sensor temperature measuring resistor is measured by the DC resistance measuring unit at the first ambient temperature. The first resistance value is obtained by calculating the average of the second resistance value and the third resistance value using the cross-correlation device.

4. The method according to claim 1, characterized in that, The step of calculating the second ambient temperature of the sensor's temperature-sensing resistor using the cross-correlation device based on the voltage divider power, the power of the thermal noise signal, and the first resistance value includes: The cross-correlation power spectrum is obtained by performing cross-correlation calculations on the power of the voltage divider and the power of the thermal noise signal using the cross-correlation device. Based on the cross-correlation power spectrum, calculate the power ratio spectrum between the thermal noise signal and the reference noise voltage signal; Based on the power ratio spectrum and the first resistance value, the second ambient temperature of the sensor's temperature measuring resistor is calculated.

5. The method according to claim 4, characterized in that, The calculation of the second ambient temperature of the sensor's temperature-sensing resistor includes: The second ambient temperature of the sensor's temperature-sensing resistor is calculated using the following formula: Where T1 represents the second ambient temperature; V ref R represents the amplitude of each frequency component of the reference noise voltage signal; T1 This indicates the first resistance value; is the fitted value obtained by least-squares fitting of the power ratio spectrum; L represents the frequency interval of each harmonic classification of the reference noise voltage signal in the frequency domain; R F1 The sum of the resistances of the first resistor and the second resistor; k is Boltzmann's constant; T is the frequency resolution of the cross-correlation power spectrum; F1 The ambient temperature is the temperature of the environment in which the first resistor and the second resistor are located.

6. The method according to claim 1, characterized in that, The method further includes: The dual-mode temperature measurement system is controlled to be in the secondary resistance thermometer temperature measurement mode. In the secondary resistance thermometer temperature measurement mode, the fourth resistance value of the sensor temperature measuring resistor is measured by the DC resistance measuring unit. The ambient temperature of the environment in which the temperature-sensing resistor of the sensor is located is calculated using the following formula: Among them, R T2 R0 is the resistance value of the sensor temperature measuring resistor at 0℃; T2 is the ambient temperature of the environment where the sensor temperature measuring resistor is located; α and β are the values ​​of the coefficients obtained after this calibration.

7. A dual-mode temperature measurement system, characterized in that, The system includes a differential reference noise source, a coaxial switch group, a probe, a cross-correlation device, and a DC resistance measurement unit. The probe includes a sensor-sensing resistor. When the sensor-sensing resistor forms a closed loop with the differential reference noise source through the coaxial switch group, and when the sensor-sensing resistor forms a closed loop with the cross-correlation device through the coaxial switch group, the dual-mode temperature measurement system is in primary noise thermometer mode. When the sensor-sensing resistor forms a closed loop with the DC resistance measurement unit through the coaxial switch group, the dual-mode temperature measurement system is in secondary resistance thermometer mode. The cross-correlation device is used to control the dual-mode temperature measurement system to be in the secondary resistance thermometer temperature measurement mode for each first ambient temperature at which the dual-mode temperature measurement system is located. The DC resistance measuring unit is used to measure the first resistance value of the sensor temperature measuring resistor at the first ambient temperature in the secondary resistance thermometer temperature measuring mode. The cross-correlation device is also used to control the dual-mode temperature measurement system to be in the primary noise thermometer temperature measurement mode, and to collect the power of the reference noise voltage signal generated by the differential reference noise source, the voltage division power on the sensor temperature measuring resistor, and the power of the thermal noise signal generated by the sensor temperature measuring resistor. The cross-correlation device is also used to calculate the second ambient temperature of the sensor temperature measuring resistor based on the voltage divider power, the power of the thermal noise signal, and the first resistance value. The cross-correlation device is further configured to, after obtaining the second ambient temperature of the sensor temperature measuring resistor and the first resistance value of the sensor temperature measuring resistor when the dual-mode temperature measurement system is respectively at each of the first ambient temperatures, perform least squares fitting on each of the second ambient temperatures and each of the first resistance values ​​to obtain the value of the coefficient used to measure the ambient temperature of the environment where the sensor temperature measuring resistor is located in the secondary resistance thermometer temperature measurement mode, so as to use the value to calibrate the historical value of the coefficient; The differential reference noise source includes a first resistor, a differential reference voltage source, and a second resistor connected in series. When the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode, the positive terminal of the differential reference voltage source is connected to the positive terminal of the coaxial switch group through the first resistor, and the negative terminal of the differential reference voltage source is connected to the negative terminal of the coaxial switch group through the second resistor. The differential reference voltage source includes a first arbitrary waveform generator and a first single-ended to differential amplifier connected in series; wherein, the positive terminal of the first single-ended to differential amplifier is connected to the first resistor, and the negative terminal of the first single-ended to differential amplifier is connected to the second resistor; Alternatively, the differential reference voltage source includes a first analog-to-digital converter and a second single-ended to differential amplifier connected in series; wherein the positive terminal of the second single-ended to differential amplifier is connected to the first resistor, and the negative terminal of the second single-ended to differential amplifier is connected to the second resistor; Alternatively, the differential reference voltage source includes a second arbitrary waveform generator and a third arbitrary waveform generator connected in series; wherein the second arbitrary waveform generator is connected to the first resistor, and the third arbitrary waveform generator is connected to the second resistor; The coaxial switch group includes six single-ended coaxial switches, each of which has three pins: a first pin, a second pin, and a third pin. The positive terminal of the temperature-sensing resistor is connected to the third pin of three of the single-ended coaxial switches via leads, and the negative terminal of the temperature-sensing resistor is connected to the third pin of the other three single-ended coaxial switches via leads. For one of the three single-ended coaxial switches connected to the positive terminal of the sensor temperature measuring resistor, the first pin of the single-ended coaxial switch is connected to the first resistor via a lead, and the second pin of the single-ended coaxial switch is connected to a floating pin via a lead. The first pins of the other two of the three single-ended coaxial switches connected to the positive terminal of the sensor temperature measuring resistor are connected to the positive terminal of the cross-correlation device via leads, and the second pins of the other two single-ended coaxial switches are connected to the positive terminal of the DC resistance measuring unit via leads. For one of the three single-ended coaxial switches connected to the negative terminal of the sensor temperature measuring resistor, the first pin of the single-ended coaxial switch is connected to the second resistor via a lead, and the second pin of the single-ended coaxial switch is connected to a floating pin via a lead. The first pins of the other two of the three single-ended coaxial switches connected to the negative terminal of the sensor temperature measuring resistor are connected to the negative terminal of the cross-correlation device via leads, and the second pins of the other two single-ended coaxial switches are connected to the negative terminal of the DC resistance measuring unit via leads. When the third pin of each of the single-ended coaxial switches is connected to the first pin of its respective single-ended coaxial switch via a lead wire, the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the third pin of each of the single-ended coaxial switches is connected to the second pin of its respective single-ended coaxial switch via a lead wire, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode. or, The coaxial switch group includes three integrated differential switches; each differential switch includes a first coaxial lead, a second coaxial lead, and a third coaxial lead; wherein the outer layer of the first coaxial lead is a first metal conductor layer, the outer layer of the second coaxial lead is a second metal conductor layer, and the outer layer of the third coaxial lead is a third metal conductor layer; the positive terminal of the sensor temperature measuring resistor is connected to the core of the third coaxial lead in each differential switch; the negative terminal of the sensor temperature measuring resistor is connected to the first metal conductor layer, the second metal conductor layer, and the third metal conductor layer. In one of the differential switches, the core of the first coaxial lead is connected to the first resistor, and the first metal conductor layer of the first coaxial lead is connected to the second resistor; the core of the second coaxial lead in the differential switch is connected to the floating leg, and the second metal conductor layer of the second coaxial lead is connected to the floating leg. For the other two differential switches, the positive terminal of the cross-correlation device is connected to the core of the first coaxial lead in the two differential switches, and the negative terminal is connected to the first metal conductor layer in the two differential switches; the positive terminal of the DC resistance measuring unit is connected to the core of the second coaxial lead in the two differential switches, and the negative terminal is connected to the second metal conductor layer of the second coaxial lead in the two differential switches. When the core of the third coaxial lead in each of the differential switches is connected to the core of the first coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the first metal conductor layer of the first coaxial lead, the dual-mode temperature measurement system is in the primary noise thermometer temperature measurement mode; when the core of the third coaxial lead in each of the differential switches is connected to the core of the second coaxial lead, and the third metal conductor layer of the third coaxial lead is connected to the second metal conductor layer of the second coaxial lead, the dual-mode temperature measurement system is in the secondary resistance thermometer temperature measurement mode. The outer layer of the probe rod is a fourth metal conductor layer. Inside the probe rod, there is a temperature-measuring resistor for the sensor and one, two, or three fourth coaxial leads. The temperature-measuring resistor for the sensor and the fourth coaxial leads are separated from the fourth metal conductor layer by a first insulating layer inside the probe rod. The outer layer of each fourth coaxial lead is a fifth metal conductor layer. Inside the fourth coaxial lead, there is a wire core, which is separated from the fifth metal conductor layer by a second insulating layer inside the fourth coaxial lead. When the probe rod is provided with a fourth coaxial lead, the positive terminal of the sensor temperature measuring resistor is connected to one end of the core of the fourth coaxial lead through the lead, and the negative terminal is connected to the fifth metal conductor layer of the fourth coaxial lead through the lead. When the coaxial switch group includes six single-ended coaxial switches, the other end of the core of the fourth coaxial lead is connected to the third pin of the three single-ended coaxial switches that are connected to the positive terminal of the sensor temperature measuring resistor through three leads, and the fifth metal conductor layer in the fourth coaxial lead is connected to the third pin of the three single-ended coaxial switches that are connected to the negative terminal of the sensor temperature measuring resistor through three leads. When the coaxial switch group includes three integrated differential switches, the other end of the core of the fourth coaxial lead is connected to the core of each of the third coaxial leads through three leads respectively, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of each of the third coaxial leads through three leads respectively. When the probe is provided with two fourth coaxial leads, the positive terminal of the sensor temperature measuring resistor is connected to one end of the core of each fourth coaxial lead through the lead, and the negative terminal is connected to the fifth metal conductor layer in each fourth coaxial lead through the lead. When the coaxial switch group includes six single-ended coaxial switches, one end of the core of the fourth coaxial lead is connected via two leads to the third pin of two single-ended coaxial switches connected to the positive terminal of the temperature-sensing resistor. The fifth metal conductor layer of the fourth coaxial lead is connected via two leads to the third pin of two single-ended coaxial switches connected to the negative terminal of the temperature-sensing resistor. The other end of the core of the fourth coaxial lead is connected via one lead to the third pin of another single-ended coaxial switch connected to the positive terminal of the temperature-sensing resistor. The fifth metal conductor layer of the fourth coaxial lead is connected via one lead to the third pin of another single-ended coaxial switch connected to the negative terminal of the temperature-sensing resistor. When the coaxial switch group includes three integrated differential switches, the other end of the core of one of the fourth coaxial leads is connected to the cores of two of the third coaxial leads respectively through two leads, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of the two third coaxial leads respectively through two leads; the other end of the core of another fourth coaxial lead is connected to the core of another third coaxial lead through one lead, and the fifth metal conductor layer of the fourth coaxial lead is connected to the third metal conductor layer of the other third coaxial lead through one lead; When the probe is equipped with three fourth coaxial leads, the positive terminal of the sensor temperature measuring resistor is connected to one end of the core of each fourth coaxial lead through the lead, and the negative terminal is connected to the fifth metal conductor layer of each fourth coaxial lead through the lead. When the coaxial switch group includes six single-ended coaxial switches, the core of each fourth coaxial lead is sequentially connected to the third pin of the single-ended coaxial switch that is connected to the positive terminal of the sensor temperature measuring resistor, and the fifth metal conductor layer of each fourth coaxial lead is sequentially connected to the third pin of the single-ended coaxial switch that is connected to the negative terminal of the sensor temperature measuring resistor. When the coaxial switch group includes three integrated differential switches, the core of each fourth coaxial lead is sequentially connected to the core of a third coaxial lead, and the fifth metal conductor layer of each fourth coaxial lead is sequentially connected to the third metal conductor layer of a third coaxial lead.

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