A programmable Josephson step voltage transition process voltage compensation circuit and method

Abstract

This invention discloses a programmable Josephson step voltage transition process voltage compensation circuit and method. First, a differential sampling driving circuit differentially samples the step voltage values ​​of the signal under test and the PJVS signal to obtain a differential sampling signal voltage value. Then, a PJVS sampling driving circuit samples the PJVS signal to obtain a PJVS sampling signal voltage value. Next, the calibration reference value of the PJVS signal is calculated based on the PJVS sampling signal voltage value, and then a temporary compensation voltage for the transition process is calculated. Finally, based on the PJVS signal step voltage value, the differential sampling signal voltage value, and the temporary compensation voltage, the compensated voltage value of the signal under test is calculated. In other words, by calculating the temporary compensation voltage for the transition process, the sampling data during the transition process is avoided, the problem of discontinuous differential signals is solved, the measurement difficulty is reduced, and the measurement error caused by discarded data is minimized, thereby improving measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of voltage compensation, and more particularly to a programmable Josephson step voltage transition process voltage compensation circuit and method. Background Technology

[0002] In 2019, the International System of Units (SI) underwent a quantum revolution. Under the new SI, the values ​​of SI base units are directly preserved and reproduced from fundamental physical constants. This revolution frees measurements from the influence of physical standards, measurement time, and environmental factors, improving measurement accuracy and stability. Among these advancements, the differential sampling power tracing scheme based on programmable Josephson step voltages (PJVS) has been widely applied both domestically and internationally. This scheme utilizes PJVS to generate precise step voltages, and through differential sampling and data processing, enables signal tracing and measurement. Both the National Institute of Metrology (NIM) of China and the National Institute of Standards and Technology (NIST) of the United States have adopted this scheme.

[0003] However, existing technologies for differential sampling using PJVS have a significant drawback: the transition process of the PJVS step voltage during rise or fall has an instability time of approximately 2µs, during which the sampled data is unusable. Therefore, existing technologies typically discard this 2µs of sampled data, but this results in discontinuous differential signals. When the frequency of the measured signal is high, such as 400Hz, the period of each step is very short (25µs), and the PJVS transition time accounts for as much as 8%. This requires very high performance from devices such as multi-function signal generators, voltage amplifiers, and transconductance amplifiers to ensure accurate reproduction of discontinuous waveforms. Moreover, as the number of steps per cycle increases, the proportion of the differential signal in the measured signal decreases. Although measurement accuracy improves, the proportion of the PJVS transition time also increases, placing higher demands on the power source. Therefore, the existing approach of discarding sampled data during the transition process leads to increased measurement difficulty and decreased measurement accuracy. Summary of the Invention

[0004] This invention provides a programmable Josephson step voltage transition process voltage compensation circuit and method, which can solve the problem that the existing technology of discarding sampled data during the transition process will lead to increased measurement difficulty and decreased measurement accuracy.

[0005] To address the aforementioned technical problems, an embodiment of the present invention provides a programmable Josephson step voltage transition process voltage compensation circuit, comprising: a differential sampling drive circuit unit, a PJVS sampling drive circuit unit, an AD conversion circuit unit, and a DSP data processing unit.

[0006] The differential sampling drive circuit unit is used to acquire the voltage value of the signal under test and the step voltage value of the PJVS signal, and to perform differential sampling and difference calculation on the voltage value of the signal under test and the step voltage value of the PJVS signal to obtain the voltage value of the differential sampled signal.

[0007] The PJVS sampling drive circuit unit is used to perform PJVS sampling on the step voltage value of the PJVS signal to obtain the PJVS sampled signal voltage value.

[0008] The AD conversion circuit unit is used to perform digital-to-analog conversion on the voltage value of the PJVS sampled signal, the step voltage value of the PJVS signal, and the voltage value of the differential sampled signal;

[0009] The DSP data processing unit is used to calculate the calibration reference value of the PJVS signal step voltage value based on the PJVS sampled signal voltage value, and to calculate the temporary compensation voltage for the step voltage transition process based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value. Finally, it calculates the compensated voltage value of the signal under test based on the PJVS signal step voltage value, the voltage value of the differential sampled signal, and the temporary compensation voltage for the step voltage transition process.

[0010] Furthermore, the programmable Josephson step voltage transition process voltage compensation circuit further includes: a first potential tracking unit, a second potential tracking unit, a first reference voltage unit, a second reference voltage unit, and a voltage divider circuit unit;

[0011] The first potential tracking unit is used to amplify and track the potential of the PJVS signal step voltage value.

[0012] The second potential tracking unit is used to amplify the voltage value of the signal under test and track and monitor its potential.

[0013] The first reference voltage unit is used to provide a first reference voltage for the differential sampling drive circuit unit and the PJVS sampling drive circuit unit;

[0014] The second reference voltage unit is used to provide a second reference voltage to the AD conversion circuit unit;

[0015] The voltage divider circuit unit is used to adjust the voltage of the PJVS signal step voltage value when the PJVS sampling drive circuit unit samples the PJVS signal step voltage value.

[0016] Furthermore, the programmable Josephson step voltage transition process voltage compensation circuit includes:

[0017] The first terminal of the first potential tracking unit is connected to the step voltage of the PJVS signal, the second terminal of the first potential tracking unit is connected to the IN+ terminal of the differential sampling drive circuit unit, and the second terminal of the first potential tracking unit is also connected to the first terminal of the voltage divider circuit unit.

[0018] The second terminal of the voltage divider circuit unit is connected to the IN+ terminal of the PJVS sampling drive circuit unit;

[0019] The IN- terminal of the PJVS sampling drive circuit unit is grounded, the output terminal of the PJVS sampling drive circuit unit is connected to the IN1+ terminal of the AD conversion circuit unit, the reference voltage terminal of the PJVS sampling drive circuit unit is connected to the IN1- terminal of the AD conversion circuit unit, and the reference voltage terminal of the PJVS sampling drive circuit unit is also connected to the first reference voltage unit.

[0020] The first terminal of the second potential tracking unit is connected to the voltage of the measured signal, and the second terminal of the second potential tracking unit is connected to the IN- terminal of the differential sampling drive circuit unit;

[0021] The output terminal of the differential sampling driving circuit unit is connected to the IN0+ terminal of the AD conversion circuit unit, the reference voltage terminal of the differential sampling driving circuit unit is connected to the IN0- terminal of the AD conversion circuit unit, and the reference voltage terminal of the differential sampling driving circuit unit is also connected to the first reference voltage unit.

[0022] The reference voltage terminal of the AD conversion circuit unit is connected to the second reference voltage unit, the output terminal of the AD conversion circuit unit is connected to the first terminal of the DSP data processing unit, and the second terminal of the DSP data processing unit is connected to the network port.

[0023] Furthermore, the differential sampling drive circuit unit consists of a first programmable gain amplifier and a first resistor.

[0024] Furthermore, the PJVS sampling drive circuit unit consists of a second programmable gain amplifier.

[0025] Furthermore, the voltage divider circuit unit consists of a second resistor and a third resistor.

[0026] Based on the above circuit embodiments, the present invention provides corresponding method embodiments;

[0027] An embodiment of the present invention provides a programmable Josephson step voltage transition process voltage compensation method, applicable to a programmable Josephson step voltage transition process voltage compensation circuit, comprising:

[0028] Obtain the voltage value of the signal under test and the step voltage value of the PJVS signal;

[0029] Differential sampling and difference calculation are performed on the voltage value of the signal under test and the step voltage value of the PJVS signal to obtain the voltage value of the differential sampled signal. Then, PJVS sampling is performed on the step voltage value of the PJVS signal to obtain the voltage value of the PJVS sampled signal.

[0030] Calculate the calibration reference value of the PJVS signal step voltage value based on the PJVS sampled signal voltage value;

[0031] Calculate the temporary compensation voltage during the step voltage transition process based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value.

[0032] The voltage value of the measured signal after compensation is calculated based on the step voltage value of the PJVS signal, the voltage value of the differential sampling signal, and the temporary compensation voltage during the step voltage transition process.

[0033] Furthermore, the calculation formula for the calibration reference value of the PJVS signal step voltage is as follows:

[0034]

[0035] Among them, V_PJ m，aver V_PJ is the calibration reference value for the voltage values ​​of m PJVS signal steps; N is the number of sampling points for each step; int() is used to round to the nearest integer; V_PJ m，n Let PJVS be the step voltage value of the sampling signal at the nth sampling point of m steps.

[0036] Furthermore, the step of calculating the temporary compensation voltage during the step voltage transition process based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value includes:

[0037] Based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value, calculate the initial step voltage transition temporary compensation voltage;

[0038] The initial temporary compensation voltage for the step voltage transition process is compared with a preset threshold. If the initial temporary compensation voltage for the step voltage transition process is greater than or equal to the preset threshold, then the initial temporary compensation voltage for the step voltage transition process is used as the temporary compensation voltage for the step voltage transition process.

[0039] Otherwise, the temporary compensation voltage for the step voltage transition process will be set to zero.

[0040] Furthermore, the calculation formula for the temporary compensation voltage during the initial step voltage transition process is as follows:

[0041]

[0042] Among them, V_PJAD_temp m，n This is a temporary compensation voltage for the initial step voltage transition process; V_PJ m，n V_PJ represents the step voltage value of the PJVS sampling signal at the nth sampling point of m steps; m，aver V_PJ is the calibration reference value for the step voltage of the m-step PJVS signal; m Let be the step voltage values ​​of the PJVS signal for m steps.

[0043] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0044] This invention first uses a differential sampling drive circuit unit to perform differential sampling and difference calculation on the voltage value of the signal under test and the step voltage value of the PJVS signal to obtain the voltage value of the differential sampled signal. Then, a PJVS sampling drive circuit unit performs PJVS sampling on the step voltage value of the PJVS signal to obtain the PJVS sampled signal voltage value. Next, based on the PJVS sampled signal voltage value, a calibration reference value for the PJVS signal step voltage value is calculated. Then, based on the PJVS sampled signal voltage value, the calibration reference value, and the PJVS signal step voltage value, a temporary compensation voltage for the step voltage transition process is calculated. Finally, based on the PJVS signal step voltage value... The voltage value of the measured signal is calculated by taking the voltage value of the differential sampling signal, the voltage value of the step voltage transition process, and the temporary compensation voltage. In other words, by calculating the temporary compensation voltage of the PJVS transition process and compensating the differential sampling signal, the sampling data during the PJVS transition process can be retained without discarding it, thus solving the problem of discontinuity in the differential signal. This reduces the performance requirements of the equipment, lowers the measurement difficulty, and reduces the measurement error caused by discarding the sampling data during the transition process by compensating for the PJVS transition process, thereby improving the measurement accuracy. This solves the problem that the existing technology's method of discarding the sampling data during the transition process leads to increased measurement difficulty and decreased measurement accuracy. Attached Figure Description

[0045] Figure 1 : A topology diagram of a programmable Josephson step voltage transition process voltage compensation circuit provided in an embodiment of the present invention;

[0046] Figure 2 This is a circuit topology diagram of the differential sampling driving circuit unit provided in an embodiment of the present invention;

[0047] Figure 3 Here is a circuit topology diagram of the PJVS sampling drive circuit unit provided in an embodiment of the present invention;

[0048] Figure 4 This is a circuit topology diagram of the voltage divider circuit unit provided in an embodiment of the present invention;

[0049] Figure 5 : A flowchart of a programmable Josephson step voltage transition process voltage compensation method provided in an embodiment of the present invention;

[0050] Figure 6 This is a fluctuation diagram of the PJVS signal and the measured signal under ideal conditions, provided by an embodiment of the present invention.

[0051] Figure 7 This is a fluctuation diagram of the differential sampling signal under ideal conditions, provided by an embodiment of the present invention.

[0052] Figure 8 This is an actual diagram of PJVS signal switching provided in an embodiment of the present invention;

[0053] Figure 9 This is a diagram showing the setting of the calibration reference value for the PJVS signal step voltage value provided in an embodiment of the present invention. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] In the description of this invention, it should be understood that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0056] Example 1:

[0057] Reference Figure 1 The above is a topology diagram of a programmable Josephson step voltage transition process voltage compensation circuit provided in an embodiment of the present invention; the circuit includes at least: a differential sampling drive circuit unit U3, a PJVS sampling drive circuit unit U2, an AD conversion circuit unit U4, a DSP data processing unit U5, a first potential tracking unit U1A, a second potential tracking unit U1B, a first reference voltage unit U6, a second reference voltage unit U7, and a voltage divider circuit unit U8;

[0058] The differential sampling drive circuit unit U3 is used to acquire the voltage value of the signal under test and the step voltage value of the PJVS signal, and to perform differential sampling and difference calculation on the voltage value of the signal under test and the step voltage value of the PJVS signal to obtain the voltage value of the differential sampled signal.

[0059] The PJVS sampling drive circuit unit U2 is used to perform PJVS sampling on the step voltage value of the PJVS signal to obtain the PJVS sampling signal voltage value.

[0060] The AD conversion circuit unit U4 is used to perform digital-to-analog conversion on the voltage value of the PJVS sampled signal, the voltage value of the PJVS signal step, and the voltage value of the differential sampled signal.

[0061] The DSP data processing unit U5 is used to calculate the calibration reference value of the PJVS signal step voltage value based on the PJVS sampled signal voltage value, and to calculate the temporary compensation voltage for the step voltage transition process based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value. Finally, it calculates the compensated voltage value of the test signal based on the PJVS signal step voltage value, the voltage value of the differential sampled signal, and the temporary compensation voltage for the step voltage transition process.

[0062] The first potential tracking unit U1A is used to amplify the PJVS signal step voltage value and monitor its potential.

[0063] The second potential tracking unit U1B is used to amplify the voltage value of the signal under test and track and monitor its potential.

[0064] The first reference voltage unit U6 is used to provide a first reference voltage for the differential sampling drive circuit unit U3 and the PJVS sampling drive circuit unit U2;

[0065] The second reference voltage unit U7 is used to provide a second reference voltage for the AD conversion circuit unit U4;

[0066] The voltage divider circuit unit U8 is used to adjust the voltage value of the PJVS signal step voltage when the PJVS sampling drive circuit unit U2 samples the PJVS signal step voltage value.

[0067] Preferably, the AD conversion circuit unit U4 adopts the AD4630-24. The AD4630-24 is a dual-channel, synchronous sampling, 2MSPS (million samples per second) successive approximation register (SAR) analog-to-digital converter (ADC) manufactured by Analog Devices (ADI), guaranteeing a maximum integral nonlinearity (INL) of ±0.9ppm and 24-bit no missing code. Since the maximum rated measurement voltage of the differential circuit is 0.08VAC and the rated measurement voltage is 0.05V, when the reference voltage of PJVS is 1VAC, the error of differential measurement is reduced by 20 times when converted to the PJVS reference voltage. Therefore, when the sampling error of differential sampling is 0.002%, the error of the entire test system can reach an accuracy of (0.002 / 20)% = 1ppm. The accuracy of the AD conversion circuit unit U4 of this invention is better than 0.002%, which can meet the requirement of 1ppm system test accuracy.

[0068] Preferably, the DSP data processing unit U5 is composed of ADI's BF609 chip and its peripherals. The chip has a large number of built-in peripherals, including one SPI interface, 16 general-purpose I / O ports, network ports, etc., 256MBYTE DRAM, used to complete the core algorithm of the present invention, communication, etc., and the SPI clock of the DSP data processing unit U5 controls the time base of the sampling process to ensure that the phase of the sampling process does not drift.

[0069] Preferably, the first reference voltage unit U6 uses the ADR441B reference chip from Analog Devices. The ADR441B has an output voltage of 2.5V, an initial accuracy of 0.04%, and a temperature coefficient of 1PPM / degree Celsius. This chip is mainly used to raise the common-mode voltage of the sampling circuit, and an accuracy of ±1% can meet the design requirements.

[0070] Preferably, the second reference voltage unit U7 uses the ADR1001E-EBZ module. The ADR1001E-EBZ module has an integrated ADR1001, which is an ultra-stable shunt reference voltage that can be easily connected to test equipment and other circuits. It has 1.2μV noise, 0.05ppm / degree Celsius temperature drift, and the output 5V voltage can be calibrated using an Agilent 3458A.

[0071] In this embodiment, the first potential tracking unit U1A and the second potential tracking unit U1B are used to amplify the PJVS signal step voltage value and the voltage value of the signal under test respectively during the sampling process of the differential sampling driving circuit unit U3 and the PJVS sampling driving circuit unit U2, so as to minimize the phase difference between the data collected by the differential sampling driving circuit unit U3 and the PJVS sampling driving circuit unit U2 and reduce the error.

[0072] Preferably, the first potential tracking unit U1A and the second potential tracking unit U1B use the OPA2210 as the main chip and are configured with emitter follower circuits. The OPA2210 is a precision low-power dual-channel 36V operational amplifier manufactured by Texas Instruments (TI). This chip is built based on TI's precision super β complementary bipolar semiconductor process and features ultra-low flicker noise, low offset voltage, and low offset voltage temperature drift. At 1kHz, its voltage noise density is only [value missing].

[0073] In this embodiment, refer to Figure 2 This is a circuit topology diagram of a differential sampling driving circuit unit provided in an embodiment of the present invention; the differential sampling driving circuit unit consists of a first programmable gain amplifier and a first resistor R. g composition.

[0074] Preferably, the first programmable gain amplifier of the differential sampling drive circuit unit adopts the AD620 chip; the amplification factor of the first programmable gain amplifier is calculated using the following formula: When Rg2 = 2.6kΩ, the amplification gain is 20 times; Rg can be composed of multiple 0.01% VISHAY precision resistors in series and parallel; the reference voltage port of the differential sampling drive circuit unit is connected to the first reference voltage unit U6 to raise the common mode voltage and match the common mode voltage (0~5V) of the AD conversion circuit U4.

[0075] In this embodiment, refer to Figure 3 The diagram shows the circuit topology of the PJVS sampling drive circuit unit provided in this embodiment of the invention; the PJVS sampling drive circuit unit is composed of a second programmable gain amplifier.

[0076] Preferably, the second programmable gain amplifier of the PJVS sampling drive circuit unit adopts the AD620 chip, and the amplification factor is 1 when the gain resistor is not connected; the reference voltage port of the PJVS sampling drive circuit unit is connected to the first reference voltage unit U6 to raise the common mode voltage and match the common mode voltage (0~5V) of the AD conversion circuit U4.

[0077] In this embodiment, refer to Figure 4 The diagram shows the circuit topology of a voltage divider circuit unit provided in an embodiment of the present invention; the voltage divider circuit unit consists of a second resistor R2 and a third resistor R1.

[0078] Preferably, the second resistor R2 and the third resistor R1 of the voltage divider circuit unit are precision resistors from VISHAY with a temperature drift of 1ppm. When the maximum output voltage of the PJVS is 10V, R2 = 9KΩ and R1 = 1KΩ. When the maximum output voltage of the PJVS is 2V, R2 = 1kΩ and R1 = 1KΩ; when the maximum output voltage of the PJVS is 2V, R2 = 0kΩ and R1 = 1KΩ.

[0079] In this embodiment, the connection method of each unit in the programmable Josephson step voltage transition process voltage compensation circuit includes:

[0080] The first terminal of the first potential tracking unit is connected to the step voltage of the PJVS signal, the second terminal of the first potential tracking unit is connected to the IN+ terminal of the differential sampling drive circuit unit, the second terminal of the first potential tracking unit is also connected to the first terminal of the voltage divider circuit unit, and the ground terminal of the first potential tracking unit is grounded.

[0081] The second terminal of the voltage divider circuit unit is connected to the IN+ terminal of the PJVS sampling drive circuit unit, and the ground terminal of the voltage divider circuit unit is grounded.

[0082] The IN- terminal of the PJVS sampling drive circuit unit is grounded, the output terminal of the PJVS sampling drive circuit unit is connected to the IN1+ terminal of the AD conversion circuit unit, the reference voltage terminal of the PJVS sampling drive circuit unit is connected to the IN1- terminal of the AD conversion circuit unit, and the reference voltage terminal of the PJVS sampling drive circuit unit is also connected to the first reference voltage unit.

[0083] The first terminal of the second potential tracking unit is connected to the voltage of the measured signal, the second terminal of the second potential tracking unit is connected to the IN- terminal of the differential sampling drive circuit unit, and the ground terminal of the second potential tracking unit is grounded.

[0084] The output terminal of the differential sampling driving circuit unit is connected to the IN0+ terminal of the AD conversion circuit unit, the reference voltage terminal of the differential sampling driving circuit unit is connected to the IN0- terminal of the AD conversion circuit unit, and the reference voltage terminal of the differential sampling driving circuit unit is also connected to the first reference voltage unit.

[0085] The reference voltage terminal of the AD conversion circuit unit is connected to the second reference voltage unit, the output terminal of the AD conversion circuit unit is connected to the first terminal of the DSP data processing unit, and the second terminal of the DSP data processing unit is connected to the network port.

[0086] In this embodiment, the ground terminals of the signal under test and the PJVS signal are grounded, and the PJVS signal is also connected to a high-stability clock.

[0087] Example 2:

[0088] Reference Figure 5 : A flowchart of a programmable Josephson step voltage transition process voltage compensation method provided in an embodiment of the present invention; the method includes at least the following steps:

[0089] Step S1: Obtain the voltage value of the signal under test and the step voltage value of the PJVS signal;

[0090] Step S2: Perform differential sampling and difference calculation on the voltage value of the signal to be measured and the step voltage value of the PJVS signal to obtain the voltage value of the differential sampled signal, and perform PJVS sampling on the step voltage value of the PJVS signal to obtain the voltage value of the PJVS sampled signal;

[0091] Step S3: Calculate the calibration reference value of the PJVS signal step voltage value based on the PJVS sampled signal voltage value;

[0092] Step S4: Calculate the temporary compensation voltage for the step voltage transition process based on the calibration reference value of the PJVS sampled signal voltage value, the PJVS signal step voltage value, and the PJVS signal step voltage value.

[0093] Step S5: Calculate the compensated voltage value of the signal under test based on the step voltage value of the PJVS signal, the voltage value of the differential sampling signal, and the temporary compensation voltage during the step voltage transition process.

[0094] In this embodiment, refer to Figure 9 This is a diagram showing the setting of the calibration reference value for the PJVS signal step voltage value provided in this embodiment of the invention; the calculation formula for the calibration reference value of the PJVS signal step voltage value is:

[0095]

[0096] Among them, V_PJ m，aver V_PJ is the calibration reference value for the voltage values ​​of m PJVS signal steps; N is the number of sampling points for each step; int() is used to round to the nearest integer; V_PJ m，n Let PJVS be the step voltage value of the sampling signal at the nth sampling point of m steps.

[0097] In this embodiment, the step of calculating the temporary compensation voltage for the step voltage transition process based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value includes:

[0098] Based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value, calculate the initial step voltage transition temporary compensation voltage;

[0099] The initial temporary compensation voltage for the step voltage transition process is compared with a preset threshold. If the initial temporary compensation voltage for the step voltage transition process is greater than or equal to the preset threshold, then the initial temporary compensation voltage for the step voltage transition process is used as the temporary compensation voltage for the step voltage transition process.

[0100] Otherwise, the temporary compensation voltage for the step voltage transition process will be set to zero.

[0101] In this embodiment, the preset threshold is set to 1uV.

[0102] In this embodiment, the formula for calculating the temporary compensation voltage during the initial step voltage transition process is as follows:

[0103]

[0104] Among them, V_PJAD_temp m，n This is a temporary compensation voltage for the initial step voltage transition process; V_PJ m，n V_PJ represents the step voltage value of the PJVS sampling signal at the nth sampling point of m steps; m，aver V_PJ is the calibration reference value for the step voltage of the m-step PJVS signal; m Let be the step voltage values ​​of the PJVS signal for m steps.

[0105] In this embodiment, the calculation of the compensated voltage value of the signal under test based on the PJVS signal step voltage value, the voltage value of the differential sampling signal, and the temporary compensation voltage during the step voltage transition process is specifically as follows:

[0106] The voltage value of the measured signal after compensation is calculated by adding the step voltage value of the PJVS signal, the voltage value of the differential sampling signal, and the temporary compensation voltage during the step voltage transition process.

[0107] For example, ideally, PJVS does not have a rising or falling transition process. Figure 6 , Figure 7 As shown; Figure 6 This is a waveform diagram of the PJVS signal and the measured signal under ideal conditions; Figure 7 The waveform of the differential sampling signal under ideal conditions is shown below. The voltage value of the signal under test and the step voltage value of the PJVS signal are tracked by potential and then differentially sampled by the differential drive circuit unit to obtain the differential sampling voltage difference. The difference measured by differential sampling is then added to the step voltage value of the PJVS signal to obtain the voltage value of the signal under test.

[0108] In practical situations, such as Figure 8 The diagram shown is an actual diagram of PJVS signal switching provided in an embodiment of the present invention. During PJVS switching, there is approximately a jitter of about 2µs. This jitter will cause errors and cannot be directly used as a reference voltage. Therefore, a programmable Josephson step voltage transition process voltage compensation method of the present invention is required.

[0109] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A programmable Josephson step voltage transition process voltage compensation circuit, characterized in that, include: Differential sampling drive circuit unit, PJVS sampling drive circuit unit, AD conversion circuit unit and DSP data processing unit; The differential sampling drive circuit unit is used to acquire the voltage value of the signal under test and the step voltage value of the PJVS signal, and to perform differential sampling and difference calculation on the voltage value of the signal under test and the step voltage value of the PJVS signal to obtain the voltage value of the differential sampled signal. The PJVS sampling drive circuit unit is used to perform PJVS sampling on the step voltage value of the PJVS signal to obtain the PJVS sampled signal voltage value. The AD conversion circuit unit is used to perform digital-to-analog conversion on the voltage value of the PJVS sampled signal, the step voltage value of the PJVS signal, and the voltage value of the differential sampled signal; The DSP data processing unit is used to calculate the calibration reference value of the PJVS signal step voltage value based on the PJVS sampled signal voltage value, and to calculate the temporary compensation voltage for the step voltage transition process based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value. Finally, it calculates the compensated voltage value of the signal under test based on the PJVS signal step voltage value, the voltage value of the differential sampled signal, and the temporary compensation voltage for the step voltage transition process.

2. The programmable Josephson step voltage transition process voltage compensation circuit according to claim 1, characterized in that, Also includes: The system comprises a first potential tracking unit, a second potential tracking unit, a first reference voltage unit, a second reference voltage unit, and a voltage divider circuit unit. The first potential tracking unit is used to amplify and track the potential of the PJVS signal step voltage value. The second potential tracking unit is used to amplify the voltage value of the signal under test and track and monitor its potential. The first reference voltage unit is used to provide a first reference voltage for the differential sampling drive circuit unit and the PJVS sampling drive circuit unit; The second reference voltage unit is used to provide a second reference voltage to the AD conversion circuit unit; The voltage divider circuit unit is used to adjust the voltage of the PJVS signal step voltage value when the PJVS sampling drive circuit unit samples the PJVS signal step voltage value.

3. The programmable Josephson step voltage transition process voltage compensation circuit according to claim 2, characterized in that, include: The first terminal of the first potential tracking unit is connected to the step voltage of the PJVS signal, the second terminal of the first potential tracking unit is connected to the IN+ terminal of the differential sampling drive circuit unit, and the second terminal of the first potential tracking unit is also connected to the first terminal of the voltage divider circuit unit. The second terminal of the voltage divider circuit unit is connected to the IN+ terminal of the PJVS sampling drive circuit unit; The IN- terminal of the PJVS sampling drive circuit unit is grounded, the output terminal of the PJVS sampling drive circuit unit is connected to the IN1+ terminal of the AD conversion circuit unit, the reference voltage terminal of the PJVS sampling drive circuit unit is connected to the IN1- terminal of the AD conversion circuit unit, and the reference voltage terminal of the PJVS sampling drive circuit unit is also connected to the first reference voltage unit. The first terminal of the second potential tracking unit is connected to the voltage of the measured signal, and the second terminal of the second potential tracking unit is connected to the IN- terminal of the differential sampling drive circuit unit; The output terminal of the differential sampling driving circuit unit is connected to the IN0+ terminal of the AD conversion circuit unit, the reference voltage terminal of the differential sampling driving circuit unit is connected to the IN0- terminal of the AD conversion circuit unit, and the reference voltage terminal of the differential sampling driving circuit unit is also connected to the first reference voltage unit. The reference voltage terminal of the AD conversion circuit unit is connected to the second reference voltage unit, the output terminal of the AD conversion circuit unit is connected to the first terminal of the DSP data processing unit, and the second terminal of the DSP data processing unit is connected to the network port.

4. The programmable Josephson step voltage transition process voltage compensation circuit according to claim 3, characterized in that, The differential sampling drive circuit unit consists of a first programmable gain amplifier and a first resistor.

5. A programmable Josephson step voltage transition process voltage compensation circuit according to claim 4, characterized in that, The PJVS sampling drive circuit unit consists of a second programmable gain amplifier.

6. A programmable Josephson step voltage transition process voltage compensation circuit according to claim 4, characterized in that, The voltage divider circuit unit consists of a second resistor and a third resistor.

7. A programmable Josephson step voltage transition process voltage compensation method, characterized in that, A programmable Josephson step voltage transition voltage compensation circuit is applicable, comprising: Obtain the voltage value of the signal under test and the step voltage value of the PJVS signal; Differential sampling and difference calculation are performed on the voltage value of the signal under test and the step voltage value of the PJVS signal to obtain the voltage value of the differential sampled signal. Then, PJVS sampling is performed on the step voltage value of the PJVS signal to obtain the voltage value of the PJVS sampled signal. Calculate the calibration reference value of the PJVS signal step voltage value based on the PJVS sampled signal voltage value; Calculate the temporary compensation voltage during the step voltage transition process based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value. The voltage value of the measured signal after compensation is calculated based on the step voltage value of the PJVS signal, the voltage value of the differential sampling signal, and the temporary compensation voltage during the step voltage transition process.

8. The programmable Josephson step voltage transition process voltage compensation method according to claim 7, characterized in that, The formula for calculating the calibration reference value of the PJVS signal step voltage is as follows: Among them, V_PJ m，aver V_PJ is the calibration reference value for the voltage values ​​of m PJVS signal steps; N is the number of sampling points for each step; int() is used to round to the nearest integer; V_PJ m，n Let PJVS be the step voltage value of the sampling signal at the nth sampling point of m steps.

9. A programmable Josephson step voltage transition process voltage compensation method according to claim 8, characterized in that, The calculation of the temporary compensation voltage during the step voltage transition process based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value includes: Based on the PJVS sampled signal voltage value, the calibration reference value of the PJVS signal step voltage value, and the PJVS signal step voltage value, calculate the initial step voltage transition temporary compensation voltage; The initial temporary compensation voltage for the step voltage transition process is compared with a preset threshold. If the initial temporary compensation voltage for the step voltage transition process is greater than or equal to the preset threshold, then the initial temporary compensation voltage for the step voltage transition process is used as the temporary compensation voltage for the step voltage transition process. Otherwise, the temporary compensation voltage for the step voltage transition process will be set to zero.

10. A programmable Josephson step voltage transition process voltage compensation method according to claim 9, characterized in that, The formula for calculating the temporary compensation voltage during the initial step voltage transition process is as follows: Among them, V_PJAD_temp m，n This is a temporary compensation voltage for the initial step voltage transition process; V_PJ m，n V_PJ represents the step voltage value of the PJVS sampling signal at the nth sampling point of m steps; m，aver V_PJ is the calibration reference value for the step voltage of the m-step PJVS signal; m Let m be the step voltage values ​​of the PJVS signal at each step.

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