Dual-mixing dual-channel attenuation measurement device and method

Abstract

The invention provides a dual-mixing dual-channel attenuation measurement device and method. The device comprises a millimeter wave signal generation device, a millimeter wave mixing system and a receiving device, wherein the millimeter wave signal generation device is used for generating a test signal through a millimeter wave frequency multiplication module and an amplitude stabilization loop by using a microwave signal source; the millimeter wave mixing system is used for performing down-mixing on the test signal generated by the millimeter wave signal generation device by adopting a harmonic mixer to obtain an intermediate frequency (IF) signal, and performing down-conversion on the IF signal by adopting a fundamental wave mixer after the IF signal passes through a tested attenuator to obtain an audio AF signal; the attenuation receiving device is used for carrying out low-noise pre-amplification on the AF signal obtained by the millimeter wave frequency mixing system, and obtaining a final voltage value after voltage division, internal amplification, filtering, direct current detection and AD sampling processing; by means of the device, the measurement dynamic range is enlarged, and the measurement precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of attenuation measurement, and in particular to a dual-mixing dual-channel attenuation measurement device and method. Background Art

[0002] Attenuation parameter is one of the basic parameters of radio measurement, and the measurement of many millimeter wave parameters is closely related to attenuation measurement. The accuracy of the attenuation parameter value is related to the measurement of the dynamic characteristics of the receiving system and the transmission characteristics of each component of the feed system. The transmission loss of millimeter waves through waveguides or in free space is very high, so a highly sensitive attenuation measurement system is required to measure millimeter wave signals. In addition, the millimeter wave attenuation measurement system can also accurately measure the high dynamic transmission loss of various microwave devices. In the millimeter wave frequency band above 50 GHz, the microwave transmission line form usually adopts a rectangular waveguide transmission line. Below 50 GHz, this method can use a coaxial transmission line.

[0003] The most commonly used method for attenuation measurement is the substitution method, which includes the radio frequency substitution method and the low intermediate frequency substitution method. The advantage of the radio frequency substitution method is that since the measured attenuation is replaced by the standard attenuation of the same frequency, the attenuation measurement is not affected by the nonlinearity of the detector. Therefore, as long as the output power of the signal source is large and the sensitivity of the receiving indication system is high, the range can be very large. However, its disadvantage is that it is necessary to have a standard attenuator with the same frequency as the device under test, and it is currently difficult to manufacture an RF standard attenuator with the same accuracy as the intermediate frequency standard attenuator. In addition, in the millimeter wave band, the size of the standard waveguide port is very small. Therefore, the polarization attenuator in this frequency band is difficult to process, has low accuracy, and is inconvenient to trace. This makes the system based on the radio frequency substitution method difficult to implement.

[0004] Therefore, how to increase the measurement dynamic range and improve the measurement accuracy has become one of the existing technical problems that need to be solved urgently. Summary of the invention

[0005] The invention provides a dual-mixing dual-channel attenuation measurement device and method, which are used to increase the measurement dynamic range and improve the measurement accuracy.

[0006] In a first aspect, a dual-mixing dual-channel attenuation measurement device is provided, comprising: a millimeter wave signal generating device, a millimeter wave mixing system and a receiving device; wherein,

[0007] The millimeter wave signal generating device is used to generate a test signal using a microwave signal source through a millimeter wave frequency multiplication module and an amplitude stabilization loop;

[0008] The millimeter wave mixing system is used to use a harmonic mixer to down-mix the test signal generated by the millimeter wave signal generating device into an intermediate frequency IF signal, pass through the attenuator under test, and then use a fundamental mixer to down-convert the IF signal to obtain an audio AF signal;

[0009] The attenuation receiving device is used to pre-amplify the AF signal obtained by the millimeter wave mixing system with low noise, obtain the final voltage value after voltage division, internal amplification, filtering, DC detection and AD sampling processing; and measure the attenuation through orthogonal correlation detection.

[0010] In one embodiment, the millimeter wave signal generating device is specifically used to use a main harmonic mixer and a reference harmonic mixer to down-convert the multiplied microwave signal to a main IF and reference IF signal of 1 GHz, respectively. The main IF signal and the reference IF signal are added to two fundamental wave mixers after filtering and amplification, and then down-converted to obtain two final AF signals.

[0011] In one embodiment, the AF signal is divided into a main AF signal and a reference AF signal. The main AF signal is pre-amplified and added to an inductive voltage divider and a phase-locked amplifier for final measurement. The reference AF signal is used to provide a reference signal to an attenuated receiving device.

[0012] In one embodiment, the main IF and reference IF signals are transmitted to an attenuator through a bandpass filter for suppressing harmonic signals.

[0013] In one implementation, four isolators are placed between the main fundamental mixer and the reference fundamental mixer to reduce leakage signals introduced into the reference channel.

[0014] In one embodiment, an adjustable attenuator is added to the front end of the attenuator under test as a substitute attenuator, which is used to measure the change of attenuation in partial steps; when the attenuation of the attenuator under test increases, the attenuation of the substitute attenuator decreases; when the attenuation of the attenuator under test decreases, the attenuation of the substitute attenuator increases, thereby reducing the change of the measurement signal.

[0015] In one embodiment, the attenuated receiving device includes a pre-amplifier, an inductive voltage divider and a lock-in amplifier.

[0016] In one implementation, the attenuated receiving device uses orthogonal correlation detection to measure the amplitude and phase of the AF signal.

[0017] In one embodiment, the process of measuring the attenuator under test by the attenuation receiving device includes:

[0018] According to the requirements of the attenuator under test, set the frequencies of the RF and local oscillator sources to the required frequency points, and according to the normal working requirements of the mixer, set the output level of the local oscillator source and the level of the RF signal source;

[0019] The variable attenuator under test is placed at the initial attenuation position A0, and the voltage divider ratio of the inductive voltage divider is placed at the initial voltage divider ratio D0, so that the lock-in amplifier receives a balanced indication;

[0020] Place the attenuator to be tested at the A1 position of the attenuation to be measured. At this time, the system loses balance due to the change of attenuation in the series system.

[0021] Adjust the voltage divider ratio of the inductive voltage divider again to balance the system again, so that the phase-locked amplifier receives the balance indication and reads the secondary voltage divider ratio D1 of the inductive voltage divider at this time. The attenuation increment A of the attenuator under test is:

[0022]

[0023] In a second aspect, a dual-mixing dual-channel attenuation measurement method is provided, the method being applied to the dual-mixing dual-channel attenuation measurement device described above, comprising:

[0024] The millimeter wave signal generating device uses a microwave signal source to generate a test signal through a millimeter wave frequency multiplication module and an amplitude stabilization loop;

[0025] The millimeter wave mixing system uses a harmonic mixer to down-mix the test signal generated by the millimeter wave signal generating device into an intermediate frequency IF signal, passes through the attenuator under test, and then uses a fundamental mixer to down-convert the IF signal to obtain an audio AF signal;

[0026] The attenuation receiving device performs low-noise pre-amplification on the AF signal obtained by the millimeter wave mixing system, obtains the final voltage value after voltage division, internal amplification, filtering, DC detection and AD sampling, and measures the attenuation through orthogonal correlation detection.

[0027] The embodiment of the present invention provides a dual-mixing dual-channel attenuation measurement device and method, the device comprising: a millimeter wave signal generating device, a millimeter wave mixing system and a receiving device; wherein the millimeter wave signal generating device is used to generate a test signal by using a microwave signal source through a millimeter wave frequency multiplication module and an amplitude stabilization loop; the millimeter wave mixing system is used to use a harmonic mixer to down-mix the test signal generated by the millimeter wave signal generating device to an intermediate frequency IF signal, pass through a measured attenuator, and then use a fundamental mixer to down-convert the IF signal to obtain an audio AF signal; the attenuation receiving device is used to pre-amplify the AF signal obtained by the millimeter wave mixing system with low noise, obtain a final voltage value after voltage division, internal amplification, filtering, DC detection and AD sampling processing; and measure the attenuation through orthogonal correlation detection. Through the above device, the measurement dynamic range is increased and the measurement accuracy is improved.

[0028] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structure particularly pointed out in the written description, claims, and drawings thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 A block diagram of a dual-mixing dual-channel attenuation measurement device according to an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of an orthogonal detection structure according to an embodiment of the present invention;

[0032] Figure 3 The figure is a flow chart of a dual-mixing dual-channel attenuation measurement method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to increase the measurement dynamic range and improve the measurement accuracy, a dual-mixing dual-channel attenuation measurement device and method are provided.

[0034] The preferred embodiments of the present invention are described below in conjunction with the drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In addition, the embodiments of the present invention and the features in the embodiments may be combined with each other if there is no conflict.

[0035] like Figure 1 As shown, the embodiment provides a dual-mixing dual-channel attenuation measurement device, including: a millimeter wave signal generating device, a millimeter wave mixing system and a receiving device; wherein,

[0036] The millimeter wave signal generating device is used to generate a test signal using a microwave signal source through a millimeter wave frequency multiplication module and an amplitude stabilization loop;

[0037] The millimeter wave mixing system is used to use a harmonic mixer to down-mix the test signal generated by the millimeter wave signal generating device into an intermediate frequency IF signal, pass through the attenuator under test, and then use a fundamental mixer to down-convert the IF signal to obtain an audio AF signal;

[0038] The attenuation receiving device is used to pre-amplify the AF signal obtained by the millimeter wave mixing system with low noise, obtain the final voltage value after voltage division, internal amplification, filtering, DC detection and AD sampling processing; and measure the attenuation through orthogonal correlation detection.

[0039] In one embodiment, the millimeter wave signal generating device is specifically used to use a main harmonic mixer and a reference harmonic mixer to down-convert the multiplied microwave signal to a main IF and reference IF signal of 1 GHz, respectively. The main IF signal and the reference IF signal are added to two fundamental wave mixers after filtering and amplification, and then down-converted to obtain two final AF signals.

[0040] In one embodiment, the AF signal is divided into a main AF signal and a reference AF signal. The main AF signal is pre-amplified and added to an inductive voltage divider and a phase-locked amplifier for final measurement. The reference AF signal is used to provide a reference signal to an attenuated receiving device.

[0041] In one embodiment, the main IF and reference IF signals are transmitted to an attenuator through a bandpass filter for suppressing harmonic signals.

[0042] In one implementation, four isolators are placed between the main fundamental mixer and the reference fundamental mixer to reduce leakage signals introduced into the reference channel.

[0043] In one embodiment, an adjustable attenuator is added to the front end of the attenuator under test as a substitute attenuator, which is used to measure the change of attenuation in partial steps; when the attenuation of the attenuator under test increases, the attenuation of the substitute attenuator decreases; when the attenuation of the attenuator under test decreases, the attenuation of the substitute attenuator increases, thereby reducing the change of the measurement signal.

[0044] In one embodiment, the attenuated receiving device includes a pre-amplifier, an inductive voltage divider and a lock-in amplifier.

[0045] In one implementation, the attenuated receiving device uses orthogonal correlation detection to measure the amplitude and phase of the AF signal.

[0046] In one embodiment, the process of measuring the attenuator under test by the attenuation receiving device includes:

[0047] According to the requirements of the attenuator under test, set the frequencies of the RF and local oscillator sources to the required frequency points, and according to the normal working requirements of the mixer, set the output level of the local oscillator source and the level of the RF signal source;

[0048] The variable attenuator under test is placed at the initial attenuation position A0, and the voltage divider ratio of the inductive voltage divider is placed at the initial voltage divider ratio D0, so that the lock-in amplifier receives a balanced indication;

[0049] Place the attenuator to be tested at the A1 position of the attenuation to be measured. At this time, the system loses balance due to the change of attenuation in the series system.

[0050] Adjust the voltage divider ratio of the inductive voltage divider again to balance the system again, so that the phase-locked amplifier receives the balance indication and reads the secondary voltage divider ratio D1 of the inductive voltage divider at this time. The attenuation increment A of the attenuator under test is:

[0051]

[0052] In the attenuation measurement in the millimeter wave frequency band, as the frequency increases, the stability of the intermediate frequency output by the single-channel measurement system is particularly poor, and cannot meet the requirements for accurate attenuation measurement. The phase noise of the oscillator increases with the increase of frequency, and the phase noise of microwave millimeter wave instruments and equipment is more prominent in characteristics than the commonly used noise coefficient. Moreover, its phase noise has also become a major influencing factor in the millimeter wave frequency band, greatly causing numerical instability in the receiving part. The embodiment provides a dual-mixing dual-channel attenuation measurement device that can more effectively generate a high-quality reference signal. The consistency of the phase noise between the reference signal source and several other signal sources can make the reference signal and the test signal of the attenuation receiving device strictly synchronized, the stability of the received intermediate frequency signal is significantly improved, and the system measurement accuracy is also improved.

[0053] The dual-channel attenuation measurement device designed by the present invention generates a phase-consistent test signal and a reference signal through a signal separation device, and then uses the relevant detection technology to significantly improve the stability of the intermediate frequency amplitude output, effectively reducing the impact of phase noise brought by the signal source and its frequency multiplication module. At the same time, the method designed by this patent effectively improves the accuracy of attenuation measurement, thereby ensuring the accuracy of microwave devices such as attenuators or transmission links. The device can be directly used for the metrological calibration of various attenuators in the millimeter wave frequency band, and at the same time provides technical guarantees for the development of related products such as low-intermediate-frequency substitution attenuation measurement instruments, and has broad application prospects in the metrological testing of microwave millimeter-wave attenuation parameters, standard development, and related product transformation.

[0054] For easier understanding, an example is given below:

[0055] The attenuation measurement device consists of three parts: millimeter wave signal generation, millimeter wave mixing system and receiving device.

[0056] Millimeter wave signal generation is used to generate the millimeter wave signal required for millimeter wave attenuation parameter calibration measurement, which is generally achieved through frequency doubling and amplitude stabilization methods. The millimeter wave signal is generated by using a microwave signal source, passing through a millimeter wave frequency doubling module and an amplitude stabilization loop. The power level stability of the signal will have a direct and significant impact on the subsequent attenuation measurement. Therefore, the millimeter wave signal should have high frequency accuracy and power level stability, as well as low phase noise.

[0057] The millimeter wave mixing system needs to down-mix the test signal, and the down-mixed signal should be a 10kHz audio AF signal. In the millimeter wave frequency band, the indicators of the fundamental mixer are reduced, the requirements for the local oscillator power level are difficult to meet the output signal of the general frequency multiplication module, and the output down-converted intermediate frequency signal is also difficult to meet the use requirements.

[0058] Therefore, this patent adopts a secondary mixing method, first using a harmonic mixer to down-convert the millimeter wave signal to a 1GHz intermediate frequency IF signal, and then using a fundamental mixer to down-convert the signal to obtain a 10kHz audio AF signal for final reception processing. In the process of two down-conversions, the linearity of the mixer is the focus.

[0059] Finally, the receiving device is used for receiving, so it must have the ability to receive small signals. At the same time, in order to meet the large dynamic requirements of the attenuation system, it must have a sufficiently wide dynamic range and low noise, as well as high sensitivity and anti-interference ability, and good stability and repeatability. The working frequency of the receiving device is 10kHz, with the ability to receive small signals, and good stability and repeatability.

[0060] The attenuation receiving device is mainly composed of three parts, including a pre-amplifier, an inductive voltage divider and a phase-locked amplifier. The function of the attenuation receiving device in the system is to pre-amplify the low intermediate frequency signal after down-mixing with low noise, and then enter the input end of the inductive voltage divider. The signal after the voltage division by the inductive voltage divider is used as the input signal of the receiving terminal, and the final voltage value is displayed after internal amplification, filtering, DC detection, A / D sampling and other processing. The attenuation to be measured is measured by reaching the same voltage value during the two balances. Therefore, the attenuation receiving device must have the ability to receive small signals, meet the requirements of large dynamics of the attenuation system, have a sufficiently wide dynamic range and low noise, as well as high sensitivity and anti-interference ability, and have good stability and repeatability.

[0061] For easier understanding, another specific example is given below:

[0062] Taking 140GHz to 220GHz as an example, as shown in Figure 1, a two-stage mixing method is used in the measurement device to first mix the 140GHz-220GHz millimeter wave signal to an intermediate frequency IF signal of 1GHz to 1.5GHz, and then perform low-noise amplification and bandpass filtering to improve the absolute power and signal-to-noise ratio of the signal. Then, the IF signal is down-converted to a 10kHz AF signal using a fundamental mixer, and then processed to determine the attenuation of the attenuator under test.

[0063] Two harmonic mixers are used to down-convert 140GHz~220GHz signals to 1GHz main IF and reference IF signals. The main IF signal and reference IF signal are added to two fundamental mixers after passing through an attenuator, and then down-converted to obtain two final 10kHz AF signals. The main AF signal is added to the inductive voltage divider and the phase-locked amplifier after pre-amplification for final measurement, and the reference AF signal is used to provide a reference signal for the attenuated receiving device.

[0064] Since the RF and LO input signals of the two mixers are derived from the same time base signal, the reference audio AF signal frequency of the reference channel can be strictly synchronized with the audio AF signal frequency of the main channel. This effectively reduces the audio signal frequency jitter caused by the phase noise of the microwave signal source in the single-channel system and the receiver detection noise generated. The problem of the external reference frequency of the attenuation receiving device of the single-channel system being out of sync with the audio AF signal frequency has also been solved. Since the reference channel provides synchronized and precise frequency information, the signal detection value of the receiver of the dual-channel measurement system is more stable, thereby greatly reducing the uncertainty of attenuation measurement in the millimeter wave band.

[0065] The microwave signal (11.67 GHz to 18.33 GHz) generates a signal in the range of 140 GHz to 220 GHz by driving a 12-fold frequency multiplier. Two subharmonic mixers are used to down-convert the millimeter wave to a main intermediate frequency signal and a reference intermediate frequency signal of 1 GHz. The main intermediate frequency signal and the reference intermediate frequency pass through a bandpass filter to suppress harmonic signals. The intermediate frequency signal is further down-converted into a 10 kHz audio frequency (AF) signal by two RF mixers. The cutoff frequency of the low-pass filter is 100 kHz. The reference AF signal provides a frequency reference for the phase-locked amplifier to stabilize the reading of the phase-locked amplifier. The inductive voltage divider provides a traceable audio voltage ratio with an accuracy of 10 -6 Four isolators are placed between the main mixer and the reference mixer to reduce the leakage signal introduced by the reference channel.

[0066] An adjustable attenuator is used to control the signal level at the input end to minimize the compression error of the primary and secondary harmonic mixers and the RF mixer. Isolators and impedance matching networks are used at the source and receiving ends to reduce reflections from the signal multiplier and the primary and secondary harmonic mixers. In addition, an adjustable attenuator is added to the front end of the attenuator under test as a substitute attenuator (Gauge Block) to partially compensate for the change in the measured attenuation. When the attenuation of the attenuator under test increases, the attenuation of the substitute attenuator decreases; when the attenuation of the attenuator under test decreases, the attenuation of the substitute attenuator increases, reducing the change in the measured signal. In this way, in the case of a larger signal source output power, while improving the large attenuation signal-to-noise ratio, the nonlinearity of the large signal is avoided.

[0067] In the attenuation measurement device, noise will limit the lower limit of the system's low power value. If the influence of noise can be reduced, the sensitivity of the system's detection signal can be improved and the dynamic range of the system can be expanded. Because the values ​​of noise at different times are unrelated, this property is very useful for signal extraction and reception in noise. If the influence of noise is to be effectively suppressed, corresponding methods such as correlation detection can be used according to its characteristics to suppress the noise to the maximum extent.

[0068] Orthogonal correlation detection can eliminate the influence of the initial phase difference between the reference signal and the test signal. For signals with different initial phase differences, the amplitude of the output signal is equal to the amplitude of the measured signal. In addition, orthogonal correlation detection can measure the phase of the signal while measuring the signal amplitude, which is very useful when measuring the zero potential of the inductive voltage divider. Through theoretical analysis and simulation experiments, it can be seen that the attenuation receiving device using orthogonal correlation detection can suppress the influence of noise to the maximum extent and improve the system resolution. The maximum small signal resolution of an ordinary narrowband measurement receiver is about 10 microvolts, while the maximum small signal resolution of the attenuation receiving device is about 10 nanovolts. Therefore, the attenuation receiving device using orthogonal correlation detection can be used as an ideal choice for the detection indicator device in the attenuation measurement system.

[0069] The process of measuring the attenuator under test by this measuring device is: first, according to the requirements of the attenuator under test, the frequencies of the RF and local oscillator sources are set to the required frequency points, and according to the normal working requirements of the mixer, the output level of the local oscillator source and the level of the RF signal source are appropriately set. The variable attenuator under test is placed at the initial attenuation A0 (zero scale) position, and the voltage divider ratio of the inductive voltage divider is placed at the D0 position, so that the phase-locked amplifier receives a balanced indication (voltage is U); then the attenuator under test is placed at the A1 position of the attenuation to be measured. At this time, due to the change in attenuation in the series system, the system loses balance. Adjust the voltage divider ratio of the inductive voltage divider again to balance the system again, even if the balanced indication voltage received by the phase-locked amplifier is still U, and read the voltage divider ratio D1 at this time. Then the attenuation increment A of the attenuator under test is:

[0070]

[0071] Where: A1-attenuation to be measured;

[0072] A0-initial attenuation;

[0073] D1-inductive voltage divider secondary voltage ratio;

[0074] D0- Initial voltage divider ratio of the inductive voltage divider.

[0075] For a step or variable attenuator, the attenuation measurement values ​​of different attenuation levels can be obtained by changing the attenuation scale and repeating the above measurement process.

[0076] Based on the same technical concept, an embodiment of the present application also provides a dual-mixing dual-channel attenuation measurement method. Since the method is applied to the above-mentioned device, the implementation of the method can refer to the implementation of the device, and the repeated parts will not be repeated.

[0077] like Figure 3 As shown, the embodiment provides a dual-mixing dual-channel attenuation measurement method, and the specific implementation steps include:

[0078] S31, the millimeter wave signal generating device generates a test signal by using a microwave signal source through a millimeter wave frequency multiplication module and an amplitude stabilization loop;

[0079] S32, the millimeter wave mixing system uses a harmonic mixer to down-mix the test signal generated by the millimeter wave signal generating device into an intermediate frequency IF signal, passes through the attenuator under test, and then uses a fundamental mixer to down-convert the IF signal to obtain an audio AF signal;

[0080] S33, the attenuation receiving device performs low-noise pre-amplification on the AF signal obtained by the millimeter wave mixing system, obtains the final voltage value after voltage division, internal amplification, filtering, DC detection and AD sampling, and measures the attenuation through orthogonal correlation detection.

[0081] The present invention innovatively adopts a dual-mixing dual-channel attenuation measurement method. The dual-channel attenuation measurement device is actually an improvement of the low intermediate frequency substitution method applied to a higher frequency range. This method uses a signal separation device to generate a measurement signal and a reference signal with strict phase consistency, and then uses correlation detection technology to significantly improve the stability of the system output intermediate frequency amplitude, effectively reducing the impact of phase noise brought by the signal source and its frequency multiplication module. The dual-mixing dual-channel attenuation test design method is the core innovation of the present invention and needs to be protected.

[0082] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0083] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A dual-mixing dual-channel attenuation measurement device, characterized in that: include: Millimeter wave signal generating device, millimeter wave mixing system and receiving device; wherein, The millimeter wave signal generating device is used to generate a test signal using a microwave signal source through a millimeter wave frequency multiplication module and an amplitude stabilization loop; The millimeter wave mixing system is used to use a harmonic mixer to down-mix the test signal generated by the millimeter wave signal generating device into an intermediate frequency IF signal, pass through the attenuator under test, and then use a fundamental mixer to down-convert the IF signal to obtain an audio AF signal; The attenuation receiving device is used to pre-amplify the AF signal obtained by the millimeter wave mixing system with low noise, obtain the final voltage value after voltage division, internal amplification, filtering, DC detection and AD sampling processing; and measure the attenuation through orthogonal correlation detection.

2. The dual-mixing dual-channel attenuation measurement device according to claim 1, characterized in that: The millimeter wave signal generating device is specifically used to use a main harmonic mixer and a reference harmonic mixer respectively to down-convert the multiplied microwave signal to a main IF and a reference IF signal of 1 GHz. The main IF signal and the reference IF signal are added to two fundamental wave mixers after filtering and amplification, and then down-converted to obtain two final AF signals.

3. The dual-mixing dual-channel attenuation measurement device according to claim 2, characterized in that: The AF signal is divided into a main AF signal and a reference AF signal. The main AF signal is added to the inductive voltage divider and the phase-locked amplifier after pre-amplification for final measurement, and the reference AF signal is used to provide a reference signal for the attenuation receiving device.

4. The dual-mixing dual-channel attenuation measurement device according to claim 3, characterized in that: The main IF and reference IF signals are transmitted to the attenuator through a bandpass filter to suppress harmonic signals.

5. The dual-mixing dual-channel attenuation measurement device according to claim 2, characterized in that: Four isolators are placed between the main fundamental mixer and the reference fundamental mixer to reduce leakage signals introduced into the reference channel.

6. The dual-mixing dual-channel attenuation measurement device according to claim 1, characterized in that: An adjustable attenuator is added to the front end of the attenuator under test as a substitute attenuator, which is used for the change of the attenuation under partial step length measurement; when the attenuation of the attenuator under test increases, the attenuation of the substitute attenuator decreases; when the attenuation of the attenuator under test decreases, the attenuation of the substitute attenuator increases, thereby reducing the change of the measurement signal.

7. The dual-mixing dual-channel attenuation measurement device according to any one of claims 1, 4 or 6, characterized in that: The attenuated receiving device comprises a pre-amplifier, an inductive voltage divider and a phase-locked amplifier.

8. The dual-mixing dual-channel attenuation measurement device according to claim 7, characterized in that: The attenuated receiving device adopts orthogonal correlation detection to measure the amplitude and phase of the AF signal.

9. The dual-mixing dual-channel attenuation measurement device according to claim 8, characterized in that: The process of measuring the attenuator under test by the attenuation receiving device includes: According to the requirements of the attenuator under test, set the frequencies of the RF and local oscillator sources to the required frequency points, and according to the normal working requirements of the mixer, set the output level of the local oscillator source and the level of the RF signal source; The variable attenuator under test is placed at the initial attenuation position A0, and the voltage divider ratio of the inductive voltage divider is placed at the initial voltage divider ratio D0, so that the lock-in amplifier receives a balanced indication; Place the attenuator to be tested at the A1 position of the attenuation to be measured. At this time, the system loses balance due to the change of attenuation in the series system. Adjust the voltage divider ratio of the inductive voltage divider again to balance the system again, so that the phase-locked amplifier receives the balance indication and reads the secondary voltage divider ratio D1 of the inductive voltage divider at this time. The attenuation increment A of the attenuator under test is:

10. A dual-mixing dual-channel attenuation measurement method, the method being applied to the dual-mixing dual-channel attenuation measurement device described in 1 to 9, characterized in that: include: The millimeter wave signal generating device uses a microwave signal source to generate a test signal through a millimeter wave frequency multiplication module and an amplitude stabilization loop; The millimeter wave mixing system uses a harmonic mixer to down-mix the test signal generated by the millimeter wave signal generating device into an intermediate frequency IF signal, passes through the attenuator under test, and then uses a fundamental mixer to down-convert the IF signal to obtain an audio AF signal; The attenuation receiving device performs low-noise pre-amplification on the AF signal obtained by the millimeter wave mixing system, obtains the final voltage value after voltage division, internal amplification, filtering, DC detection and AD sampling, and measures the attenuation through orthogonal correlation detection.

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