Multi-resistance calibration method and multi-resistance calibration system for high-precision amplitude-frequency characteristic of operational amplifier

Abstract

The invention provides a multi-resistance calibration method and a multi-resistance calibration system for high-precision amplitude-frequency characteristics of an operational amplifier, and the method comprises the steps: receiving a to-be-detected signal from an antenna, enabling the to-be-detected signal to reach the operational amplifier through a microwave switch, enabling the to-be-detected signal to reach a receiver after the to-be-detected signal is amplified by the operational amplifier, and obtaining a first receiving signal; switching the microwave switch from the antenna to the calibration resistors, and switching among the plurality of calibration resistors, so that a signal generated by the calibration resistors passes through the microwave switch and the operational amplifier and then reaches the receiver through each switched-on calibration resistor circuit to obtain a second receiving signal, and obtaining the temperature of the calibration resistors; substituting the second receiving signal of each calibration resistor circuit and the temperature of the calibration resistor into a preset operational amplifier signal transmission model, and solving the value of an unknown parameter contained in the operational amplifier signal transmission model; and solving the calibrated to-be-measured signal from the antenna by taking the to-be-measured signal from the antenna as an unknown number, and further obtaining the amplitude-frequency characteristic of the operational amplifier.

Description

Technical Field

[0001] The present invention relates to the technical field of high-precision ultra-wideband radio frequency microwave measurement, and in particular to a multi-resistance calibration method and a multi-resistance calibration system for high-precision amplitude-frequency characteristics of an operational amplifier. Background Art

[0002] In high-precision ultra-wideband RF microwave measurements, accurate acquisition of signal amplitude and frequency information is crucial for many scientific research and application scenarios, such as high-precision signal and spectrum measurement, radio astronomy detection, etc. In traditional methods, in order to ensure the maximum power transmission of the signal, the broadband matching problem has long restricted the bandwidth range of signal transmission, limiting the effective operation of the measurement system in a wider frequency range. Using operational amplifiers to directly amplify antenna signals is a promising method.

[0003] The operational amplifier has the remarkable characteristic of high input impedance, which enables more voltage signals to enter the amplifier, making it possible to break through the limitation of bandwidth caused by broadband matching problem. The antenna signal is amplified by the operational amplifier, and the voltage signal is received by using the high input impedance characteristic of the operational amplifier. Since there is no need to consider the maximum power transmission, the limitation of bandwidth caused by matching problem is effectively broken through, which can ensure that the signal can be stably transmitted and processed in a very wide frequency range.

[0004] However, high-precision ultra-wideband RF microwave measurement based on operational amplifiers is a typical application in high-frequency scenarios. When used in high-frequency scenarios, operational amplifier calibration is extremely difficult. As the frequency increases to more than tens of megahertz, the influence of signal mismatch effect makes the calibration difficulty of operational amplifiers increase exponentially. In addition, gain instability and inherent noise inside the operational amplifier further aggravate this difficulty. The lack of this calibration technology has led to the inability to effectively guarantee the performance of operational amplifiers in high-frequency ultra-wideband measurements, which has seriously hindered the further development and application of related technologies.

[0005] Existing amplifier calibration technologies (such as DCOC calibration, DC offset calibration circuits, etc.) lack accurate calibration of operational amplifiers used at high frequencies. Research on calibration of operational amplifiers above tens of megahertz is almost blank. Currently, there is no mature technical solution that can achieve accurate calibration of operational amplifiers at high frequencies.

[0006] Therefore, how to provide an operational amplifier five-resistance calibration module and calibration method suitable for high-frequency scenarios to effectively solve the operational amplifier calibration problem at high frequencies is a technical problem that needs to be solved urgently. Summary of the invention

[0007] In view of this, an embodiment of the present invention provides a multi-resistance calibration method and a multi-resistance calibration system for the high-precision amplitude-frequency characteristic of an operational amplifier, so as to overcome the problem of difficult calibration of the operational amplifier faced in high-precision ultra-wideband measurement when operating at high frequencies.

[0008] One aspect of the present invention provides a multi-resistance calibration method for the high-precision amplitude-frequency characteristic of an operational amplifier. The method includes the following steps: receiving a signal to be measured from an antenna, passing the signal to be measured through a microwave switch to an operational amplifier, and after being amplified by the operational amplifier, reaching a receiver, so as to obtain a first received signal; wherein, one input port of the microwave switch is connected to the antenna, and the other has multiple input ports respectively connected to multiple calibration resistors with different resistances, and the output port of the microwave switch is connected to the operational amplifier; switching the microwave switch from the antenna to the calibration resistor and switching between multiple calibration resistors, so that the signal generated by the calibration resistor passes through the microwave switch and the operational amplifier and then reaches the receiver through each connected calibration resistor circuit, thereby obtaining a second received signal, and acquiring the temperature of the calibration resistor in the current calibration resistor circuit measured simultaneously; substituting the second received signal and the temperature of the calibration resistor of each calibration resistor circuit into a preset operational amplifier signal transmission model to solve for the values of the unknown parameters included in the operational amplifier signal transmission model; wherein, the number of unknown parameters included in the operational amplifier signal transmission model corresponds to the number of calibration resistors with different resistances, and in the preset operational amplifier signal transmission model, the signal generated by the calibration resistor is calculated through the quantitative relationship between the temperature of the calibration resistor and the signal generated by the calibration resistor; using the signal to be measured from the antenna as an unknown, substituting the obtained values of the unknown parameters and the first received signal into the operational amplifier signal transmission model, solving for the signal to be measured from the antenna after calibration, and further obtaining the amplitude-frequency characteristic of the operational amplifier.

[0009] In some embodiments of the present invention, the method further includes: calculating the antenna temperature through the quantitative relationship between the antenna temperature and the signal to be measured from the antenna after calibration in the preset operational amplifier signal transmission model.

[0010] In some embodiments of the present invention, the unknown parameters include an operational amplifier gain coefficient and multiple noise parameters, and the multiple noise parameters include multiple types of current noise, voltage noise, real part of the correlation term between current noise and voltage noise, and imaginary part of the correlation term between current noise and voltage noise.

[0011] In some embodiments of the present invention, the number of the multiple calibration resistors is five, the operational amplifier signal transmission model includes five unknown parameters, and each calibration resistor forms a path through the microwave switch to connect to a calibration resistor circuit of the operational amplifier and the receiver; correspondingly, the mathematical expression of the operational amplifier signal transmission model is: ; Among them, for the antenna represents the first received signal, for the calibration resistor represents the second received signal, for the calibration resistor represents the resistance temperature, for the antenna represents the antenna temperature, for the calibration resistor represents the calibration resistor value, for the antenna represents the antenna resistance value, is the Boltzmann constant, is the ambient temperature introduced by the radio frequency line loss, is the propagation coefficient from the antenna or calibration resistor to the receiver, is the parallel value of all the impedances in front of the receiver and the receiver impedance, and are respectively the real part and the imaginary part of the impedance parallel value ; among them, the five unknown parameters include: the operational amplifier gain coefficient , the current noise , the voltage noise , the real part of the correlation term between the current noise and the voltage noise, and the imaginary part of the correlation term between the current noise and the voltage noise.

[0012] In some embodiments of the present invention, the preset resistance values of the calibration resistors are different, and the method further includes: determining the resistance value of each calibration resistor in advance through an error analysis algorithm.

[0013] In some embodiments of the present invention, the multi-resistance calibration method is applicable to high-frequency scenarios.

[0014] Correspondingly to the above method, the present invention also provides a multi-resistance calibration system for the high-precision amplitude-frequency characteristic of an operational amplifier, including: a calibration module, including a microwave switch and a plurality of calibration resistors. One input port of the microwave switch is connected to an antenna, and the other has a plurality of input ports respectively connected to a plurality of calibration resistors with different resistances. The output port of the microwave switch is connected to the operational amplifier. Wherein, the calibration module is configured to receive a signal to be measured from the antenna, enable the signal to be measured to reach the operational amplifier through the microwave switch, and reach the receiver after being amplified by the operational amplifier, so as to obtain a first received signal; switch the microwave switch from the antenna to the calibration resistor and switch between the plurality of calibration resistors. The calibration module is further configured to enable the signal generated by the calibration resistor to reach the receiver through the microwave switch and the operational amplifier through the calibration resistor circuit connected in each path, so as to obtain a second received signal, and acquire the temperature of the calibration resistor in the current calibration resistor circuit measured simultaneously; an operation unit, configured to substitute the second received signal of each calibration resistor circuit and the temperature of the calibration resistor into a preset operational amplifier signal transmission model, solve the value of the unknown parameter included in the operational amplifier signal transmission model, and then take the signal to be measured from the antenna as an unknown number, substitute the solved value of the unknown parameter and the first received signal into the operational amplifier signal transmission model, solve the signal to be measured from the antenna after calibration, and further obtain the amplitude-frequency characteristic of the operational amplifier. Wherein, the number of unknown parameters included in the operational amplifier signal transmission model corresponds to the number of calibration resistors with different resistances, and the signal generated by the calibration resistor is calculated through the quantitative relationship between the temperature of the calibration resistor and the signal generated by the calibration resistor in the preset operational amplifier signal transmission model.

[0015] In some embodiments of the present invention, the system further includes an operational amplifier and a receiver, and the receiver is configured to receive the first received signal and the second received signal.

[0016] In some embodiments of the present invention, the operation unit is further configured to calculate the antenna temperature through the quantitative relationship between the antenna temperature and the signal to be measured from the antenna after calibration in the preset operational amplifier signal transmission model.

[0017] In some embodiments of the present invention, the unknown parameters include an operational amplifier gain coefficient and a plurality of noise parameters, and the plurality of noise parameters include multiple types of current noise, voltage noise, real part of the correlation term between current noise and voltage noise, and imaginary part of the correlation term between current noise and voltage noise.

[0018] The multi-resistance calibration method and system for the high-precision amplitude-frequency characteristic of an operational amplifier proposed by the present invention can construct a calibration resistance network by introducing a multi-path calibration resistance circuit, obtain a set of data through each calibration resistance circuit, substitute the data into the operational amplifier signal transmission model to solve for unknown parameters, and these unknown parameters are correlated with noise. Then, substitute the solved unknown parameters back into the operational amplifier signal transmission model to obtain a result that eliminates the influence of noise. This method can expand the application scenario of the operational amplifier to high-frequency scenarios, effectively eliminate the signal propagation effect in high-frequency scenarios, and is conducive to ensuring accurate signal calibration in high-frequency scenarios by modeling the propagation effect, filling the gap in the calibration technology of operational amplifiers in high-frequency working conditions. Moreover, this solution only needs to add multiple resistors and a microwave switch to the hardware to achieve accurate calibration. Compared with the existing traditional calibration circuits, it does not require complex active devices and strict resistor constant temperature control conditions. The simple design in this solution is conducive to reducing the system complexity, improving the system integration level, reducing cost investment, reducing potential failure points due to the simplification of the structure, and making the system more stable and reliable in practical applications.

[0019] Additional advantages, objects, and features of the present invention will be partially described below and will become partially apparent to those of ordinary skill in the art after studying the following. Or they can be learned from the practice of the present invention. The objects and other advantages of the present invention can be realized and obtained by the structure specifically pointed out in the specification and the drawings.

[0020] Those skilled in the art will understand that the objects and advantages that can be achieved by the present invention are not limited to the above specifically described, and the above and other objects that the present invention can achieve will be more clearly understood according to the following detailed description. Brief Description of the Drawings

[0021] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and do not limit the present invention. In the drawings: Figure 1 It is a flowchart of the multi-resistance calibration method for the high-precision amplitude-frequency characteristic of an operational amplifier in an embodiment of the present invention.

[0022] Figure 2 It is a structural diagram of the multi-resistance calibration system for the high-precision amplitude-frequency characteristic of an operational amplifier in an embodiment of the present invention. Detailed Embodiments

[0023] To make the objects, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the embodiments and the drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not limit the present invention.

[0024] Here, it should also be noted that in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the present invention are shown in the drawings, while other details less relevant to the present invention are omitted.

[0025] It should be emphasized that the term "comprising / including" when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0026] Here, it should also be noted that if not otherwise specified, the term "connection" in this text can not only refer to direct connection, but also represent indirect connection with an intermediate object.

[0027] In the following, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0028] In order to overcome the problem of difficult calibration of operational amplifiers in high-precision ultra-wideband measurements when operating at high frequencies, the present invention proposes a multi-resistance calibration method for the high-precision amplitude-frequency characteristics of operational amplifiers. The microwave switch has multiple ports, and each calibration resistor is connected to one port of the microwave switch.

[0029] Figure 1 It is a flowchart of the multi-resistance calibration method for the high-precision amplitude-frequency characteristics of an operational amplifier in an embodiment of the present invention. The method includes the following steps: Step S110: Receive the signal to be measured from the antenna, make the signal to be measured pass through the microwave switch to reach the operational amplifier, and after being amplified by the operational amplifier, reach the receiver, so as to obtain the first received signal. Among them, one input port of the microwave switch is connected to the antenna, and it also has multiple input ports respectively connected to multiple calibration resistors with different resistances. The output port of the microwave switch is connected to the operational amplifier.

[0030] Step S120: Switch the microwave switch from the antenna to the calibration resistor and switch between multiple calibration resistors, so that the signal generated by the calibration resistor passes through the microwave switch and the operational amplifier and then reaches the receiver through each connected calibration resistor circuit, so as to obtain the second received signal, and obtain the temperature of the calibration resistor in the current calibration resistor circuit measured simultaneously.

[0031] Among them, since the calibration resistor has temperature, it will generate thermal noise (also known as Johnson–Nyquist noise). In the specific implementation process, the resistance temperature of the calibration resistor is used in the operational amplifier signal transmission model to represent the signal of the true input , the signal generated by the calibration resistor. Similarly, the antenna temperature is used to represent the signal to be measured from the antenna 。In the field of radio astronomy, it is further possible to solve for the antenna temperature 。In this solution, when the circuit is split, for each circuit path, the antenna temperature and the resistance temperature are in an equivalent substitution relationship, the first received signal and the second received signal are in an equivalent substitution relationship, and the calibration resistance value and the antenna resistance value are in an equivalent substitution relationship.

[0032] It should be noted that in this solution, generally speaking, the unknown parameters in the system vary with temperature and voltage. Therefore, the unknown parameters and the resistance temperature used to calculate the unknown parameters need to be measured and calculated in real time.

[0033] Step S130: Substitute the second received signal of each calibration resistance circuit and the temperature of the calibration resistance into a preset operational amplifier signal transmission model to solve for the values of the unknown parameters included in the operational amplifier signal transmission model; wherein, the number of unknown parameters included in the operational amplifier signal transmission model corresponds to the number of calibration resistors with different resistance values, and in the preset operational amplifier signal transmission model, the signal generated by the calibration resistance is calculated through the quantitative relationship between the temperature of the calibration resistance and the signal generated by the calibration resistance.

[0034] It should be noted that in the specific implementation process, the number of calibration resistors may exceed the number of unknown parameters, and the excess calibration resistors can be used to verify the correctness of the results.

[0035] Step S140: Using the signal to be measured from the antenna as the unknown, substitute the obtained values of the unknown parameters and the first received signal into the operational amplifier signal transmission model to solve for the calibrated signal to be measured from the antenna, and further obtain the amplitude-frequency characteristic of the operational amplifier.

[0036] Among them, the operational amplifier signal transmission model is a mathematical model representing the quantitative relationship between the signal of the true input (using the resistance temperature or the antenna temperature to represent the signal generated by the resistance or the signal to be measured from the antenna) and the received signal received by the receiver (here, the signal after the signal to be measured passes through the operational amplifier is called the first received signal, and the signal after the calibration signal passes through the operational amplifier is called the second received signal). Regarding the utilization of the operational amplifier signal transmission model, first, the unknown parameters such as the operational amplifier gain coefficient and multiple noise parameters are solved in real time through a multi-path calibration resistance circuit, and then the obtained unknown parameters are substituted into the operational amplifier signal transmission model, the resistance temperature is equivalent to the antenna temperature, the antenna temperature or the signal to be measured from the antenna is used as the unknown parameter, and the signal to be measured from the antenna is solved, and the antenna temperature can be further calculated based on the signal to be measured.

[0037] By adopting the multi-resistance calibration method for the high-precision amplitude-frequency characteristic of the operational amplifier proposed in the present invention, a calibration resistor network can be constructed by introducing a multi-path calibration resistor circuit. A set of data can be obtained through each calibration resistor circuit, and the data is substituted into the operational amplifier signal transmission model to solve for unknown parameters. These unknown parameters are correlated with noise. Then, the solved unknown parameters are substituted back into the operational amplifier signal transmission model, thereby obtaining a result that eliminates the influence of noise. This method can expand the application scenario of the operational amplifier to high-frequency scenarios, effectively eliminate the signal propagation effect in high-frequency scenarios, and is conducive to ensuring accurate signal calibration in high-frequency scenarios by modeling the propagation effect, filling the blank of the calibration technology of the operational amplifier under high-frequency working conditions. Moreover, this solution only needs to add multiple resistors and a microwave switch to the hardware to achieve accurate calibration. Compared with the existing traditional calibration circuit, it does not require complex active devices and strict resistor constant temperature control conditions. The simple design in this solution is conducive to reducing the system complexity, improving the system integration level, reducing cost investment, and reducing potential fault points due to the simplification of the structure, making the system more stable and reliable in practical applications.

[0038] In some embodiments of the present invention, the method further includes: calculating the antenna temperature in the preset operational amplifier signal transmission model through the quantitative relationship between the antenna temperature and the to-be-tested signal from the antenna after calibration.

[0039] By adopting the embodiment of the present invention, an implementation manner of an operational amplifier transmission model is given.

[0040] In some embodiments of the present invention, the unknown parameters include the operational amplifier gain coefficient and multiple noise parameters, and the multiple noise parameters include multiple types among current noise, voltage noise, the real part of the correlation term between current noise and voltage noise, and the imaginary part of the correlation term between current noise and voltage noise.

[0041] By adopting the embodiment of the present invention, the noise parameters affecting the accuracy of the operational amplifier are defined from multiple angles, which is conducive to eliminating the noise influence from different angles during the calibration process and is conducive to improving the working accuracy of the operational amplifier in high-frequency scenarios.

[0042] In some embodiments of the present invention, the number of multiple calibration resistors is five, the operational amplifier signal transmission model includes five unknown parameters, and each calibration resistor forms a path through a microwave switch to connect to the calibration resistor circuit of the operational amplifier and the receiver.

[0043] Correspondingly, the mathematical expression of the operational amplifier signal transmission model is: 。

[0044] Among them, for the antenna represents the first received signal, and for the calibration resistor Denote the second received signal, using the first item within square brackets Denote the signal to be measured, for the calibration resistor Denote the resistance temperature, for the antenna Denote the antenna temperature, for the calibration resistor Denote the calibration resistor value, for the antenna Denote the antenna resistance value Is the Boltzmann constant, the second item Is the ambient temperature introduced by the RF line loss Is the propagation coefficient from the antenna or calibration resistor to the receiver Is the parallel value of all the impedances in front of the receiver and the receiver impedance, the third item in the operational amplifier signal transmission model Denote the contribution of the current noise to the received signal And Are respectively the parallel impedance values Of the real part and the imaginary part, the fourth item Denote the contribution of the voltage noise to the received signal, the last item Denote the contribution of the correlation term of the noise current and the noise voltage to the received signal. Among them, the five unknown parameters include: the operational amplifier gain coefficient , the current noise , the voltage noise , the real part of the correlation term of the current noise and the voltage noise And the imaginary part of the correlation term of the current noise and the voltage noise .

[0045] It should be noted that in radio astronomy, the antenna temperature can be used to characterize the signal magnitude, but they are not exactly equal. Its relationship with the square of the voltage is , Denote the received signal, whose physical meaning is voltage. In the field of radio astronomy, what is desired is the antenna temperature. Therefore, this scheme can be used not only to obtain the signal to be measured after calibration, but also to quantify based on the relationship between the square of the voltage and the antenna temperature, and calculate the antenna temperature after calibration

[0046] It should be noted that for each calibration resistor circuit, there are only the above five unknown parameters, and the rest of the parameters are known. For the signal to be measured, the signal to be measured Is used as the unknown, or the antenna temperature Is used as the unknown parameter

[0047] By adopting the embodiment of the invention, a method for realizing the operational amplifier signal transmission model is proposed. The present solution is not limited thereto. In fact, those skilled in the art can adjust the mathematical expressions of unknown parameters and formulas, especially the categories of noise parameters, etc. on this basis. By adopting this operational amplifier signal transmission model, the effects caused by transmission effect, loss effect, mismatch effect, gain instability, and inherent voltage noise, current noise and related noise inside the amplifier when the operational amplifier receives the signal can be effectively eliminated. Experimental tests have proved that the method proposed by the present invention can calibrate the operational amplifier to an accuracy of more than one ten-thousandth, effectively reducing the signal reception error.

[0048] In some embodiments of the present invention, the preset resistance values ​​of the calibration resistors are different, and the method further includes: determining the resistance value of each calibration resistor in advance by an error analysis algorithm.

[0049] By adopting the embodiment of the invention, the resistance value determined by the error analysis algorithm can, on the one hand, design a resistance value combination that is more convenient to calculate; on the other hand, by adjusting the resistance value combination, the numerical value substituted into the operational amplifier signal transmission model can have obvious differences, thereby effectively ensuring the quality of the calibrated results.

[0050] In the specific implementation process, the port of the microwave switch includes an input port and an output port, the antenna is connected to the input port of the microwave switch to input the signal to be measured, the calibration resistor is connected to the input port of the microwave switch, and the output port of the microwave switch is connected to the amplifier.

[0051] By adopting this embodiment of the invention, a microwave switch is used to periodically switch between various resistors, so that the signals generated by different calibration resistors are received by the operational amplifier in sequence through the microwave switch, so that multiple groups of data can be collected and the values ​​of preset unknown parameters can be solved by the simultaneous equations of the multiple groups of data.

[0052] In some embodiments of the present invention, the multi-resistance calibration method is applicable to high-frequency fields, and its operating frequency covers at least the range of 30-200MHz. Through experimental tests, it can be seen that the five-resistance operational amplifier calibration system built based on the method proposed in the present invention has a spectrum restoration accuracy of one ten-thousandth in the operating frequency range of 30-200MHz. This method can significantly improve the quality and accuracy of astronomical observation data.

[0053] Based on the method proposed by the present invention above, it can be used for ultra-high-precision and high-input-impedance all-sky spectral measurement during the cosmic dawn period. In a receiver for ultra-high-precision and high-input-impedance all-sky spectral measurement during the cosmic dawn period, the calibration technique proposed by the present invention can be applied to achieve precise calibration of the observed spectrum. In practical applications, this calibration module can be placed before the first-stage operational amplifier of the receiver. After the system is started, it will automatically trigger the operation of the five-resistance hardware calibration module. The collected data is processed by the five-resistance calibration algorithm to obtain parameters related to the system gain and system noise, and based on this, the true sky spectrum is restored. After actual testing, after adopting this technology, within the working frequency range of 30 - 200 MHz of the spectral measurement system, the spectral restoration accuracy reaches one in ten thousand, effectively improving the quality and accuracy of astronomical observation data.

[0054] Corresponding to the above method, the present invention also proposes a multi-resistance calibration system for the high-precision amplitude-frequency characteristic of an operational amplifier. Figure 2 The following is a structural diagram of the multi-resistance calibration system for the high-precision amplitude-frequency characteristic of an operational amplifier in an embodiment of the present invention. This system includes: A calibration module, including a microwave switch and multiple calibration resistors. One input port of the microwave switch is connected to the antenna, and it has multiple input ports respectively connected to multiple calibration resistors with different resistances. The output port of the microwave switch is connected to the operational amplifier. Among them, the calibration module is used to receive the signal to be measured from the antenna, enable the signal to be measured to reach the operational amplifier through the microwave switch, and after being amplified by the operational amplifier, reach the receiver, thereby obtaining a first received signal; switch the microwave switch from the antenna to the calibration resistor and switch between multiple calibration resistors. The calibration module is also used to make the signal generated by the calibration resistor pass through the microwave switch and the operational amplifier and reach the receiver through each connected calibration resistor circuit, thereby obtaining a second received signal, and obtaining the temperature of the calibration resistor in the current calibration resistor circuit measured simultaneously.

[0055] In the specific implementation process, when the number of calibration resistors is five, this calibration module can be called a five-resistance hardware calibration module. This five-resistance hardware calibration module consists of a microwave switch and five calibration resistors. The resistance values of the calibration resistors are selected through an error analysis algorithm. Each port of the microwave switch is respectively connected to a calibration resistor to form a calibration resistor network. Its input end is connected to the antenna, and the output end is connected to the operational amplifier. During the actual working process, the microwave switch switches between each resistor according to a preset cycle. In this way, signals generated by different calibration resistors can be sequentially received by the operational amplifier through the microwave switch, providing signal samples for subsequent calibration work.

[0056] When the calibration module is working, the microwave switch continuously switches between five known resistors, and the five system parameters are calculated using the model through the signals of different calibration resistors. The obtained system parameters are substituted back into the equation and combined with the signal received when the microwave switch is switched to the antenna to calibrate the actual received signal.

[0057] The operation unit is used to substitute the second received signal of each calibration resistor circuit and the temperature of the calibration resistor into a preset operational amplifier signal transmission model, solve the value of the unknown parameter contained in the operational amplifier signal transmission model, and then use the signal to be measured from the antenna as an unknown number, substitute the solved value of the unknown parameter and the first received signal into the operational amplifier signal transmission model, solve the calibrated signal to be measured from the antenna, and further obtain the amplitude-frequency characteristic of the operational amplifier; wherein the number of unknown parameters contained in the operational amplifier signal transmission model corresponds to the number of calibration resistors with different resistance values, and the signal generated by the calibration resistor is calculated in the preset operational amplifier signal transmission model through the quantitative relationship between the temperature of the calibration resistor and the signal generated by the calibration resistor.

[0058] In a specific implementation process, the computing unit is further used to calculate the antenna temperature through a quantitative relationship between the antenna temperature in a preset operational amplifier signal transmission model and the calibrated signal to be measured from the antenna.

[0059] like Figure 2 As shown, when the number of calibration resistors is 5 (i.e., calibration resistors 1 to 5), the corresponding number of unknown parameters is also 5. Therefore, the values ​​of the unknown parameters can be solved by the simultaneous equations of the operational amplifier transmission model.

[0060] In some embodiments of the present invention, the system may further include: an operational amplifier and a receiver, wherein the receiver is configured to receive the first received signal and the second received signal.

[0061] In some embodiments of the present invention, the unknown parameters include an operational amplifier gain coefficient and multiple noise parameters, and the multiple noise parameters include multiple ones of current noise, voltage noise, real part of current noise and voltage noise correlation terms, and imaginary part of current noise and voltage noise correlation terms.

[0062] In some embodiments of the present invention, Figure 2As shown, the ports of the microwave switch include an input port and an output port. The signal under test can be connected through one of the input ports of the microwave switch, or the antenna can be connected to the input port of the microwave switch to input the signal under test. The calibration resistor is connected to the input port of the microwave switch, and the output port of the microwave switch is connected to the amplifier. The operation unit obtains, on the one hand, the signal generated by the calibration resistor in the measured calibration resistor circuit, and on the other hand, the first received signal and the second received signal obtained by the receiver. Moreover, the operating frequency of the multi-resistance calibration system is in the range of 30 - 200 MHz.

[0063] In some embodiments of the present invention, the mathematical expression of the operational amplifier signal transmission model is: ; Among them, for the antenna represents the first received signal, for the calibration resistor represents the second received signal, for the calibration resistor represents the resistance temperature, for the antenna represents the antenna temperature, for the calibration resistor represents the calibration resistance value, for the antenna represents the antenna resistance value, is the Boltzmann constant, is the ambient temperature introduced by the RF line loss, is the propagation coefficient from the antenna or calibration resistor to the receiver, is the parallel value of all the impedances in front of the receiver and the receiver impedance, and are the real part and the imaginary part of the parallel impedance value respectively. Among them, the five unknown parameters include: the operational amplifier gain coefficient , the current noise , the voltage noise , the real part of the correlation term between the current noise and the voltage noise, and the imaginary part of the correlation term between the current noise and the voltage noise.

[0064] It should be noted that the above-mentioned above is always the received signal received by the receiver. The above formula needs to pass through to restore the antenna temperature . The antenna temperature is the information to be obtained. In the field of astronomy, the true input signal under test can be characterized by temperature, and temperature is used to replace the signal strength. When calculating the unknown parameters, it is necessary to switch between five resistors through the microwave switch. At this time, the received signal and the resistance temperature All are measurable. By solving five equations simultaneously, five unknown parameters can be calculated. After obtaining the five unknown parameters, substituting the antenna signal into the formula can yield the antenna temperature. .

[0065] Furthermore, in some embodiments of the present invention, it may also refer to the truly input signal to be measured. In the field of astronomy, temperature can be used to replace signal intensity. Generally speaking, in the calibration resistor circuit, the resistor temperature is the truly signal to be measured, while the received signal is the signal truly received by the receiver after passing through the operational amplifier circuit. The noise (i.e., the part to be calibrated) in this process is in the formula. Therefore, it is necessary to first solve the unknown parameters causing the perturbation, and then substitute the solved unknown parameters into the operational amplifier signal transmission model to solve for the originally unknown antenna temperature (which can also be the truly input signal to be measured quantitatively represented based on the antenna temperature ). .

[0066] The key points and advantages of the method and system proposed by the present invention include but are not limited to: (1) High-precision measurement: By combining the multi-channel calibration resistor circuit and the operational amplifier signal transmission model, it is possible to eliminate the influence caused by the transmission effect, loss effect, mismatch effect, gain instability, and the inherent voltage noise, current noise, and related noise inside the amplifier when the operational amplifier receives the signal. Experiments have proved that this solution can achieve an accuracy of more than one ten-thousandth for the calibration of the operational amplifier, effectively reducing the signal reception error.

[0067] (2) Applicable to high-frequency scenarios: The method proposed in this solution fully considers the signal propagation effect in high-frequency scenarios. By modeling the propagation effect, an operational amplifier signal transmission model is constructed, which is conducive to ensuring accurate signal calibration even in high-frequency scenarios, filling the gap in the calibration problem of operational amplifiers under high-frequency working conditions.

[0068] (3) Broadening the reception bandwidth: Compared with the limitation of the reception signal bandwidth caused by the matching problem between the operational amplifier and the antenna in traditional spectrum measurement equipment, this solution adopts a five-resistance calibration algorithm based on considering voltage transmission, fully considering the mismatch problem between the operational amplifier and the antenna during the calibration process, significantly broadening the reception bandwidth, and better meeting the requirements for bandwidth. (4) Reducing system complexity and cost: This solution only requires five resistors and one microwave switch to achieve precise calibration. Compared with traditional calibration techniques, it does not require complex active devices and strict resistor constant temperature control conditions. This simple design not only reduces system complexity, improves system integration, but also reduces cost investment. At the same time, due to the simplified system structure and fewer potential failure points, the system is more stable and reliable in practical applications.

[0069] (5) Broad technical prospects: The method proposed in this invention can accurately restore the characteristics of real measurement signals, providing a solid, reliable, accurate and efficient technical support for high-precision ultra-wideband measurement, facilitating the scientific research and application development in related fields, breaking through the technical bottleneck in the field of high-frequency operational amplifier calibration, bringing new development opportunities for high-precision ultra-wideband measurement, and having extremely important technical innovation value and practical significance.

[0070] Those of ordinary skill in the art should understand that the various exemplary components, systems, and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Specifically, whether to implement it in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, a plug-in, a functional card, and so on. When implemented in software, the elements of the present invention are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium or transmitted via a data signal carried in a carrier wave on a transmission medium or a communication link.

[0071] It should be clear that the present invention is not limited to the specific configurations and processes described above and illustrated in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and illustrated as examples. However, the method process of the present invention is not limited to the specific steps described and illustrated. Those skilled in the art can make various changes, modifications, and additions, or change the order of the steps after understanding the spirit of the present invention.

[0072] In the present invention, the features described and / or illustrated for one embodiment can be used in the same or similar manner in one or more other embodiments, and / or combined with the features of other embodiments or replace the features of other embodiments.

[0073] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-resistance calibration method for high-precision amplitude-frequency characteristics of an operational amplifier, characterized in that: The method comprises: Receive a signal to be tested from an antenna, so that the signal to be tested reaches an operational amplifier through a microwave switch, and reaches a receiver after being amplified by the operational amplifier, thereby obtaining a first received signal; wherein one input port of the microwave switch is connected to the antenna, and the other has multiple input ports respectively connected to multiple calibration resistors with different resistance values, and the output port of the microwave switch is connected to the operational amplifier; Switching the microwave switch from the antenna to the calibration resistor and switching between the multiple calibration resistors, so that the signal generated by the calibration resistor passes through the microwave switch and the operational amplifier through each connected calibration resistor circuit to reach the receiver, thereby obtaining a second receiving signal and obtaining the temperature of the calibration resistor in the current calibration resistor circuit measured at the same time; Substituting the second received signal of each calibration resistor circuit and the temperature of the calibration resistor into a preset operational amplifier signal transmission model, solving the value of the unknown parameter included in the operational amplifier signal transmission model; wherein the number of unknown parameters included in the operational amplifier signal transmission model corresponds to the number of calibration resistors with different resistance values, and calculating the signal generated by the calibration resistor in the preset operational amplifier signal transmission model through the quantitative relationship between the temperature of the calibration resistor and the signal generated by the calibration resistor; The signal to be measured from the antenna is taken as an unknown number, and the value of the unknown parameter and the first received signal are substituted into the operational amplifier signal transmission model to obtain the calibrated signal to be measured from the antenna, and further obtain the amplitude-frequency characteristic of the operational amplifier.

2. The method according to claim 1, characterized in that The method further comprises: calculating the antenna temperature in a preset operational amplifier signal transmission model through a quantitative relationship between the antenna temperature and the calibrated signal to be measured from the antenna.

3. The method according to claim 2, characterized in that The unknown parameters include an operational amplifier gain coefficient and a plurality of noise parameters, wherein the plurality of noise parameters include a plurality of current noise, voltage noise, a real part of a current noise and voltage noise correlation term, and an imaginary part of a current noise and voltage noise correlation term.

4. The method according to claim 3, characterized in that: The number of the plurality of calibration resistors is five, the operational amplifier signal transmission model includes five unknown parameters, and each calibration resistor forms a calibration resistor circuit connected to the operational amplifier and the receiver through a microwave switch; Accordingly, the mathematical expression of the operational amplifier signal transmission model is: ； Among them, for the antenna Indicates the first received signal, for the calibration resistor Indicates the second received signal, for the calibration resistor Indicates the resistance temperature, for antenna Indicates the antenna temperature, for the calibration resistor Indicates the calibration resistance value for the antenna Indicates the antenna resistance value, is the Boltzmann constant, The ambient temperature introduced by the RF line loss, is the propagation coefficient from the antenna or calibration resistor to the receiver, is the parallel value of all impedances before the receiver and the receiver impedance, and The impedance parallel value is The real and imaginary parts of The five unknown parameters include: operational amplifier gain factor , current noise , voltage noise , the real part of the current noise and voltage noise related terms And the imaginary part of the current noise and voltage noise correlation .

5. The method according to claim 1, characterized in that The preset resistance values ​​of the calibration resistors are different, and the method further includes: determining the resistance value of each calibration resistor in advance by an error analysis algorithm.

6. The method according to claim 1, characterized in that The multi-resistance calibration method is suitable for high-frequency scenarios.

7. A multi-resistance calibration system for high-precision amplitude-frequency characteristics of an operational amplifier, characterized in that: include: A calibration module, comprising a microwave switch and a plurality of calibration resistors, wherein one input port of the microwave switch is connected to an antenna, and the other input ports are respectively connected to a plurality of calibration resistors with different resistance values, and an output port of the microwave switch is connected to an operational amplifier; wherein the calibration module is used to receive a signal to be measured from the antenna, so that the signal to be measured reaches the operational amplifier through the microwave switch, and reaches the receiver after being amplified by the operational amplifier, thereby obtaining a first received signal; the microwave switch is switched from the antenna to the calibration resistor, and is switched between the plurality of calibration resistors, and the calibration module is also used to make the signal generated by the calibration resistor reach the receiver after passing through the microwave switch and the operational amplifier through each connected calibration resistor circuit, thereby obtaining a second received signal, and obtaining the temperature of the calibration resistor in the current calibration resistor circuit measured simultaneously; The operation unit is used to substitute the second received signal of each calibration resistor circuit and the temperature of the calibration resistor into a preset operational amplifier signal transmission model, solve the value of the unknown parameter contained in the operational amplifier signal transmission model, and then use the signal to be measured from the antenna as an unknown number, substitute the solved value of the unknown parameter and the first received signal into the operational amplifier signal transmission model, solve the calibrated signal to be measured from the antenna, and further obtain the amplitude-frequency characteristic of the operational amplifier; wherein the number of unknown parameters contained in the operational amplifier signal transmission model corresponds to the number of calibration resistors with different resistance values, and the signal generated by the calibration resistor is calculated in the preset operational amplifier signal transmission model through the quantitative relationship between the temperature of the calibration resistor and the signal generated by the calibration resistor.

8. The multi-resistance calibration system according to claim 7, characterized in that: The system further includes an operational amplifier and a receiver, wherein the receiver is configured to receive the first received signal and the second received signal.

9. The multi-resistance calibration system according to claim 7, characterized in that: The operation unit is also used to calculate the antenna temperature through the quantitative relationship between the antenna temperature in the preset operational amplifier signal transmission model and the calibrated signal to be measured from the antenna.

10. The multi-resistance calibration system according to claim 7, characterized in that: The unknown parameters include an operational amplifier gain coefficient and a plurality of noise parameters, wherein the plurality of noise parameters include a plurality of current noise, voltage noise, a real part of a current noise and voltage noise correlation term, and an imaginary part of a current noise and voltage noise correlation term.

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