Temperature drift suppression compensation system for atomic frequency standard

Abstract

The invention relates to the technical field of atomic frequency standards, in particular to a temperature drift suppression compensation system for an atomic frequency standard, which comprises a measured atomic frequency standard, a reference atomic frequency standard, a high and low temperature test box, a temperature measurement unit, a frequency adjustment unit, a frequency measurement unit and a temperature drift suppression compensation unit, wherein the tested atomic frequency standard is arranged in the high and low temperature test box; the measured atomic frequency standard outputs frequency signals to the frequency adjusting unit and the frequency measuring unit respectively; the reference atomic frequency standard outputs a reference signal to the frequency measurement unit; the temperature measurement unit is electrically connected with the high and low temperature test box and the temperature drift suppression compensation unit respectively; the frequency adjustment unit and the frequency measurement unit are electrically connected with the temperature drift suppression compensation unit. According to the invention, the temperature characteristics, accuracy and long-term stability of the cesium clock and the hydrogen clock can be improved by researching the temperature characteristics of the cesium atom frequency standard and the hydrogen atom frequency standard for the time keeping system and compensating the temperature drift suppression of the cesium atom frequency standard and the hydrogen atom frequency standard.

Description

Technical Field

[0001] The present application relates to the technical field of atomic frequency standards, and in particular to a temperature drift suppression and compensation system for atomic frequency standards. Background Art

[0002] At present, foreign hydrogen atomic frequency standards and cesium atomic frequency standards have good temperature characteristics, and the temperature coefficient is better than ±5×10 -15 / ℃, but the compensation design for temperature drift suppression is not considered at the whole machine level. The temperature coefficient of domestic hydrogen atomic clocks and cesium atomic clocks is relatively low, which has a great impact on long-term frequency stability, and thus affects high-end typical applications such as timekeeping.

[0003] In order to solve this problem, it is necessary to optimize the product characteristics and improve the environmental characteristics including the temperature coefficient. In addition, it is also necessary to consider and implement temperature drift suppression compensation from the time-frequency system level to improve the timekeeping performance indicators of domestic atomic clocks. Summary of the invention

[0004] The present application provides a temperature drift suppression compensation system for an atomic frequency standard. After temperature drift compensation adjustment and optimization, the temperature coefficient of the atomic frequency standard is reduced by at least 1 times, which can improve the temperature characteristics, accuracy and long-term stability of cesium clocks and hydrogen clocks and will not deteriorate due to temperature changes.

[0005] In order to achieve the above-mentioned purpose, the present application provides a temperature drift suppression and compensation system for an atomic frequency standard, comprising an atomic frequency standard to be measured, a reference atomic frequency standard, a high and low temperature test chamber, a temperature measurement unit, a frequency adjustment unit, a frequency measurement unit and a temperature drift suppression and compensation unit, wherein: the atomic frequency standard to be measured is arranged inside the high and low temperature test chamber; the atomic frequency standard to be measured outputs frequency signals to the frequency adjustment unit and the frequency measurement unit respectively; the reference atomic frequency standard outputs a reference signal to the frequency measurement unit; the temperature measurement unit is electrically connected to the high and low temperature test chamber and the temperature drift suppression and compensation unit respectively, and is used to measure the ambient temperature value of the atomic frequency standard to be measured, and upload it to the temperature drift suppression and compensation unit; the frequency adjustment unit and the frequency measurement unit are both electrically connected to the temperature drift suppression and compensation unit, and the frequency adjustment unit is also electrically connected to the frequency measurement unit, and is used to output an adjusted time signal to the frequency measurement unit, and the frequency measurement unit is used to measure the frequency difference value of the output signals of the atomic frequency standard to be measured and the reference atomic frequency standard; the temperature drift suppression and compensation unit calculates the temperature coefficient of the atomic frequency standard to be measured by collecting the temperature value of the temperature measurement unit and the frequency difference value of the frequency measurement unit.

[0006] Furthermore, the atomic frequency standard to be measured is a hydrogen atomic clock or a cesium atomic clock, which outputs a 10 MHz frequency signal.

[0007] Furthermore, the reference atomic frequency standard is an active hydrogen clock, whose index is more than one order of magnitude higher than that of the atomic frequency standard being measured.

[0008] Furthermore, the temperature range controlled by the high and low temperature test chamber is -50°C to +100°C.

[0009] Furthermore, the temperature measurement unit is composed of a plurality of temperature measuring probes, the temperature measurement range is -50°C to +100°C, the measurement resolution is 0.001°C, and the measurement accuracy is ±0.01°C.

[0010] Furthermore, the frequency micro-step resolution of the frequency adjustment unit is 1×10 -19 .

[0011] Furthermore, the frequency measurement unit performs phase measurement and comparison after mixing the frequency signal of the measured atomic frequency standard and the reference signal of the reference atomic frequency standard.

[0012] The temperature drift suppression and compensation system for an atomic frequency standard provided in the present application has the following beneficial effects:

[0013] The present application can improve the temperature characteristics, accuracy and long-term stability of cesium clocks and hydrogen clocks by studying the temperature characteristics of cesium atomic frequency standards and hydrogen atomic frequency standards used in timekeeping systems and compensating for their temperature drift suppression. The temperature coefficient of the atomic frequency standard after temperature drift compensation adjustment and optimization is reduced by at least 1 times, and the index will not deteriorate due to temperature changes, thereby improving the timekeeping performance index of the atomic clock. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0015] Figure 1 is a schematic diagram of a temperature drift suppression and compensation system for an atomic frequency standard provided according to an embodiment of the present application;

[0016] Figure 2 This is the principle diagram of the test process before temperature coefficient compensation of hydrogen atom frequency standard;

[0017] Figure 3 This is the principle diagram of the test process after the temperature coefficient of the hydrogen atom frequency standard is compensated;

[0018] In the figure: 1-atomic frequency standard to be measured, 2-high and low temperature test chamber, 3-reference atomic frequency standard, 4-temperature measurement unit, 5-frequency adjustment unit, 6-frequency measurement unit, 7-temperature drift suppression compensation unit. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0020] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0022] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0023] In addition, the term "plurality" shall mean two or more.

[0024] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] like Figure 1As shown, the present application provides a temperature drift suppression and compensation system for an atomic frequency standard, including a measured atomic frequency standard 1, a reference atomic frequency standard 3, a high and low temperature test chamber 2, a temperature measurement unit 4, a frequency adjustment unit 5, a frequency measurement unit 6 and a temperature drift suppression and compensation unit 7, wherein: the measured atomic frequency standard 1 is arranged inside the high and low temperature test chamber 2; the measured atomic frequency standard 1 outputs frequency signals to the frequency adjustment unit 5 and the frequency measurement unit 6 respectively; the reference atomic frequency standard 3 outputs a reference signal to the frequency measurement unit 6; the temperature measurement unit 4 is electrically connected to the high and low temperature test chamber 2 and the temperature drift suppression and compensation unit 7 respectively. The temperature measurement unit 4 is used to measure the ambient temperature of the atomic frequency standard 1 under test, and upload it to the temperature drift suppression compensation unit 7; the frequency adjustment unit 5 and the frequency measurement unit 6 are both electrically connected to the temperature drift suppression compensation unit 7, and the frequency adjustment unit 5 is also electrically connected to the frequency measurement unit 6, and is used to output the adjusted time signal to the frequency measurement unit 6, and the frequency measurement unit 6 is used to measure the frequency difference between the output signals of the atomic frequency standard 1 under test and the reference atomic frequency standard 3; the temperature drift suppression compensation unit 7 calculates the temperature coefficient of the atomic frequency standard 1 under test by collecting the temperature value of the temperature measurement unit 4 and the frequency difference value of the frequency measurement unit 6.

[0026] Specifically, the temperature drift suppression and compensation system for atomic frequency standards provided in the embodiment of the present application is mainly for improving the environmental adaptability of the timekeeping system. The temperature coefficient of the atomic frequency standard after adjustment and optimization by the temperature drift suppression and compensation system is reduced by at least 1 times. Among them, the atomic frequency standard 1 under test outputs a frequency signal to the frequency adjustment unit 5; the atomic frequency standard 1 under test is placed in the high and low temperature test box 2, and the temperature is changed by setting a temperature curve; the reference atomic frequency standard 3 outputs a reference signal to the frequency measurement unit 6; the temperature measurement unit 4 measures the temperature values ​​of the high and low temperature test box 2 and the atomic frequency standard 1 under test and uploads them to the temperature drift suppression and compensation unit 7; the frequency adjustment unit 5 adjusts the 10MHz output frequency signal of the atomic frequency standard 1 under test by the temperature drift suppression frequency adjustment amount set by the temperature drift suppression and compensation unit 7; the frequency measurement unit Element 6 measures the relative frequency characteristics of the 10Mhz signal of the atomic frequency standard 1 under test and the 10MHz output signal of the reference atomic frequency standard 3, and uploads them to the temperature drift suppression compensation unit 7; the temperature drift suppression compensation unit 7 receives the temperature value and the frequency difference value, calculates the temperature coefficient of the atomic frequency standard 1 under test, calculates the temperature drift suppression frequency adjustment amount of the atomic frequency standard 1 under test through the relative frequency deviation and the atomic frequency standard temperature coefficient, feeds back the temperature drift suppression frequency adjustment amount to the frequency adjustment unit 5, and outputs the adjusted time-frequency signal, thereby completing the frequency compensation of the atomic frequency standard 1 under test.

[0027] Further, the atomic frequency standard 1 to be measured is a hydrogen atomic clock or a cesium atomic clock, which outputs a 10 MHz frequency signal. In the embodiment of the present application, the atomic frequency standard 1 to be measured is preferably a hydrogen atomic clock or a cesium atomic clock, which has a temperature range of 18°C ​​to 27°C and outputs a 10 MHz frequency signal to the frequency adjustment unit 5 and the frequency measurement unit 6.

[0028] Furthermore, the reference atomic frequency standard 3 is an active hydrogen clock, and its index is more than one order of magnitude higher than that of the measured atomic frequency standard 1. The reference atomic frequency standard 3 is used to output a 10 MHz frequency signal to the frequency measurement unit 6 as a reference frequency signal.

[0029] Furthermore, the temperature range controlled by the high and low temperature test chamber 2 is -50°C to +100°C. The high and low temperature test chamber 2 is used to control the ambient temperature of the atomic frequency standard 1 under test. Its temperature control range is -50°C to +100°C. The temperature curve is set to simulate the ambient temperature change of the atomic frequency standard 1 under test. The temperature is set according to the actual situation and with reference to the temperature gradient table.

[0030] Furthermore, the temperature measurement unit 4 is composed of a plurality of temperature measuring probes, the temperature measurement range is -50°C to +100°C, the measurement resolution is 0.001°C, and the measurement accuracy is ±0.01°C. In the embodiment of the present application, the temperature measurement unit 4 is preferably composed of 8 temperature measuring probes, and the 8 temperature measuring probes are respectively arranged in the front, back, left, right, top cover and nearby environmental space of the atomic frequency standard 1 to be measured, and the measured temperature value is uploaded to the temperature drift suppression compensation unit 7. The temperature drift suppression compensation unit 7 uses the comprehensive averaging method and the Kalman filtering method to eliminate abnormal values ​​for the 8-channel temperature measurement results, thereby obtaining a more accurate and reliable ambient temperature measurement result, and realizing accurate measurement of the ambient temperature change of the atomic frequency standard 1 to be measured.

[0031] Furthermore, the frequency micro-step resolution of the frequency adjustment unit 5 is 1×10 -19 In the present application, the frequency micro-step resolution of the frequency adjustment unit 5 is preferably 1×10 -19 , which meets the 1×10 -14 / ℃, its working principle is to lock the frequency signal output by the atomic frequency standard 1 under test, and at the same time apply the precision adjustment amount f calculated by the temperature drift suppression compensation unit 7 to the loop, generate adjusted time and frequency signals, and transmit the adjusted time signal to the frequency measurement unit 6.

[0032] Furthermore, the frequency measurement unit 6 performs phase measurement and comparison after mixing the frequency signal of the measured atomic frequency standard 1 and the reference signal of the reference atomic frequency standard 3, and performs secondary calculation on the phase data output by the previous module through the internal processor, outputs the frequency data and the standard Allan variance, displays them on the software interface of the temperature drift suppression and compensation unit 7, receives the time signal adjusted by the frequency adjustment unit 5, performs frequency difference calculation, and sends the calculated result to the temperature drift suppression and compensation unit 7.

[0033] Specifically, the temperature drift suppression and compensation unit 7 can query and collect the time-frequency characteristics such as the relative frequency deviation and frequency stability of the atomic frequency standard 1 under test measured by the display frequency measurement unit 6, and collect the temperature value measured by the temperature measurement unit 4 to calculate the temperature coefficient of the atomic frequency standard 1 under test; calculate the temperature frequency drift adjustment amount of the atomic frequency standard 1 under test through the relative frequency deviation and the temperature coefficient of the atomic frequency standard, feed back the temperature frequency drift adjustment amount to the frequency adjustment unit 5, and output the adjusted time-frequency signal; the adjusted time-frequency signal is compared and calculated with the 10MHz reference signal by the frequency measurement unit 6, and the calculated result is sent to the software of the temperature drift suppression and compensation unit 7 for display, thereby completing the comparison of the indicators before and after the system compensation.

[0034] More specifically, in order to verify the effectiveness of the temperature drift suppression and compensation system for an atomic frequency standard provided in an embodiment of the present application, the atomic frequency standard 1 to be tested takes a hydrogen atomic frequency standard as an example, and the frequency characteristics of the hydrogen atomic frequency standard before and after temperature drift suppression and compensation can be tested and compared using the following process:

[0035] like Figure 2 As shown in the figure, the relative frequency difference test process before temperature coefficient compensation of hydrogen atomic frequency standard is carried out, that is, the hydrogen clock to be tested is placed in a constant temperature room or a constant temperature box, the reference hydrogen clock outputs a 10MHz frequency signal connected to the reference signal channel of VCH-314, and the measured hydrogen clock outputs a 10MHz frequency signal connected to the measured channel of VCH-314, and the frequency difference between the measured hydrogen clock signal and the reference hydrogen clock signal is measured by VCH-314; the temperature is set to 23℃, maintained at this temperature, and the frequency difference measurement data for 10 hours is collected by computer; the temperature is set to 18℃, maintained at this temperature, and the frequency difference measurement data for 10 hours is collected by computer; the temperature is set to 27℃, maintained at this temperature, and the frequency difference measurement data for 10 hours is collected by computer; by measuring the relative frequency deviation between the reference hydrogen clock and the measured hydrogen clock, the relative accuracy of each temperature section is calculated as the temperature change, and the average value is taken as the temperature coefficient of the measured hydrogen clock, which is about 4×10 -13 ;

[0036] like Figure 3As shown in the figure, the relative frequency difference test process after temperature coefficient compensation of hydrogen atomic frequency standard is carried out. That is, the hydrogen clock to be tested is placed in a constant temperature room or a constant temperature box, and a temperature probe is used to measure the temperature of the constant temperature box or the temperature near the surface of the hydrogen atomic clock. The 10MHz frequency signal output by the reference hydrogen clock and the temperature measurement result are connected to the temperature drift suppression compensation system. The 10MHz signal output by the temperature drift suppression compensation system is then connected to the reference signal channel of VCH-314. The 10MHz frequency signal output by the hydrogen clock to be tested is connected to the tested channel of VCH-314. 4 Measure the frequency difference between the measured hydrogen clock signal and the reference hydrogen clock signal; set the temperature to 23°C, maintain this temperature, and use a computer to collect 10 hours of frequency difference measurement data; set the temperature to 18°C, maintain this temperature, and use a computer to collect 10 hours of frequency difference measurement data; set the temperature to 27°C, maintain this temperature, and use a computer to collect 10 hours of frequency difference measurement data; by measuring the relative frequency deviation between the reference hydrogen clock and the measured hydrogen clock, calculate the change of relative accuracy of each temperature section with temperature, and take the average value as the temperature coefficient of the measured hydrogen clock, which is about 1×10 -14 ;

[0037] By comparing the temperature coefficients during the two tests, it can be seen that after the adjustment and optimization of the temperature drift suppression compensation system, the temperature coefficient of the atomic frequency standard has been reduced by at least 1 times.

[0038] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A temperature drift suppression and compensation system for an atomic frequency standard, characterized in that: It includes the atomic frequency standard to be measured, the reference atomic frequency standard, the high and low temperature test chamber, the temperature measurement unit, the frequency adjustment unit, the frequency measurement unit and the temperature drift suppression compensation unit, wherein: The atomic frequency standard to be measured is arranged inside the high and low temperature test box; The atomic frequency standard under test outputs frequency signals to the frequency adjustment unit and the frequency measurement unit respectively; The reference atomic frequency standard outputs a reference signal to the frequency measurement unit; The temperature measurement unit is electrically connected to the high and low temperature test box and the temperature drift suppression and compensation unit respectively, and is used to measure the ambient temperature value of the atomic frequency standard under test, and upload it to the temperature drift suppression and compensation unit; The frequency adjustment unit and the frequency measurement unit are both electrically connected to the temperature drift suppression compensation unit, and the frequency adjustment unit is also electrically connected to the frequency measurement unit, and is used to output an adjusted time signal to the frequency measurement unit, and the frequency measurement unit is used to measure the frequency difference value of the output signal of the measured atomic frequency standard and the reference atomic frequency standard; The temperature drift suppression compensation unit calculates the temperature coefficient of the atomic frequency standard being measured by collecting the temperature value of the temperature measurement unit and the frequency difference value of the frequency measurement unit.

2. The temperature drift suppression and compensation system for an atomic frequency standard according to claim 1, characterized in that: The atomic frequency standard to be measured is a hydrogen atomic clock or a cesium atomic clock, which outputs a 10 MHz frequency signal.

3. The temperature drift suppression and compensation system for an atomic frequency standard according to claim 2, characterized in that: The reference atomic frequency standard is an active hydrogen clock, and its index is more than one order of magnitude higher than that of the atomic frequency standard being measured.

4. The temperature drift suppression and compensation system for an atomic frequency standard according to claim 3, characterized in that: The temperature range controlled by the high and low temperature test box is -50°C to +100°C.

5. The temperature drift suppression and compensation system for an atomic frequency standard according to claim 4, characterized in that: The temperature measurement unit is composed of a plurality of temperature measuring probes, the temperature measurement range is -50°C to +100°C, the measurement resolution is 0.001°C, and the measurement accuracy is ±0.01°C.

6. The temperature drift suppression and compensation system for an atomic frequency standard according to claim 5, characterized in that: The frequency micro-step resolution of the frequency adjustment unit is 1×10 -19 .

7. The temperature drift suppression and compensation system for an atomic frequency standard according to claim 6, characterized in that: The frequency measurement unit performs phase measurement and comparison after mixing the frequency signal of the atomic frequency standard to be measured and the reference signal of the reference atomic frequency standard.

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