Microwave source phase noise measuring method, device and system and signal processing circuit

Abstract

The invention provides a microwave source phase noise measurement method, device and system and a signal processing circuit, and relates to the technical field of microwave source phase noise measurement. The system outputs a master optical signal, a first slave optical signal and a second slave optical signal through a first optical phase-locked loop and a second optical phase-locked loop in the signal processing circuit; the frequency difference between the main optical signal and the first slave optical signal and the frequency difference between the main optical signal and the second slave optical signal are the sum of the frequency of the microwave signal to be measured and an intermediate frequency, and modulating the microwave signal to be measured onto the main optical signal to obtain a modulated optical signal; and obtaining the phase noise of the microwave signal to be measured according to a first microwave signal obtained by combining the modulated optical signal and the first slave optical signal and then carrying out photoelectric conversion, and a second microwave signal obtained by combining the modulated optical signal and the second slave optical signal and then carrying out photoelectric conversion. The complexity of the high-frequency signal measurement process can be reduced, the measurement sensitivity is improved, the operation time is shortened, and production and popularization are easy.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave source phase noise measurement, and in particular to a microwave source phase noise measurement method, device, system and signal processing circuit. Background Art

[0002] With the continuous development of microwave oscillator technology, microwave signal synthesis technologies that can generate ultra-high frequency and low phase noise continue to emerge, such as optoelectronic oscillator (OEO) and electro-optical frequency division. The synthesized microwave signal has a very high signal frequency, which poses a great challenge to the existing microwave signal phase noise measurement technology.

[0003] Among the main phase noise measurement methods currently, the direct spectrum method is the simplest and most direct. The signal to be tested is input into the spectrum analyzer to measure the power spectrum density of the oscillator, but this method cannot distinguish between amplitude noise and phase noise; the phase detection method can overcome the above problems and convert the phase difference of the two input signals into the voltage at the output of the phase detector, but its sensitivity and test bandwidth are limited by the reference source; the frequency detection method based on the optical delay line does not need to set a reference source, which can overcome the problem that the test bandwidth is limited by the reference source, and has low power loss and high theoretical sensitivity, but in practical applications, there are additional phase noise of the link amplifier and Rayleigh scattering noise in the optical fiber, and the longer optical fiber delay line is greatly affected by the environment, which is inconvenient in practical applications. In addition, although the longer delay line can improve the sensitivity, it limits the maximum offset frequency (the difference between the actual output frequency and the set value). On top of this, a commonly used improvement method is the method of using a heterodyne phase detector to measure the phase noise of a microwave source. A specific example is the Keysight E5052B signal source analyzer, which uses a heterodyne phase detector to measure the phase noise of a microwave source and combines dual-channel cross-correlation technology to measure microwave phase noise. This method has a wide phase noise measurement range and does not require an analog delay line. In addition, the dual-channel cross-correlation technology can achieve excellent measurement sensitivity without very good hardware performance, effectively suppressing the noise of the low noise amplifier (LNA) and analog-to-digital converter (ADC) in the link. However, in order to measure high-frequency signals, it is necessary to pre-divide the frequency band for down-conversion, which makes the structure complex, and the increase in the number of cross-correlation levels will affect the measurement speed.

[0004] It can be seen that the current microwave source phase noise measurement method is greatly limited in the phase noise measurement range. Even if it can measure high-frequency signals, the measurement process is relatively complicated and will affect the measurement speed. In addition, since the phase noise measurement process of high-frequency signals is relatively complicated, the related measurement equipment is also relatively expensive and difficult to popularize. Summary of the invention

[0005] The present invention provides a microwave source phase noise measurement method, device, system and signal processing circuit, which are used to solve the defects of the prior art that the phase noise measurement process of high-frequency signals in microwave source phase noise measurement is relatively complicated and the noise measurement range is greatly limited, so as to achieve the purpose of reducing the complexity of the high-frequency signal measurement process and improving the measurement speed while ensuring high measurement sensitivity.

[0006] The present invention provides a method for measuring microwave source phase noise, comprising the following steps.

[0007] Receive a first microwave signal and a second microwave signal from a signal processing circuit; wherein the signal processing circuit includes a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit includes a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combined optical coupler and a second combined optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end by the first branch optical coupler, the first branch output end and the first output end of the first slave laser are connected to the first The input end of the optical coupler of the combined optical coupler and the output end of the first optical coupler are connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second combined optical coupler, and the output end of the second combined optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the second crystal oscillator; based on the first optical The phase-locked loop is characterized in that the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combined optical coupler, a fourth combined optical coupler, a third photodetector and a fourth photodetector, the input end of the phase modulator is connected to the second output end of the master laser, and the output end of the phase modulator is divided into the third combined optical coupler and the fourth combined optical coupler through the second branch optical coupler. The branch output end and the fourth branch output end, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combined optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combined optical coupler, the output end of the third combined optical coupler is connected to the third photodetector, and the output end of the fourth combined optical coupler is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main optical signal output by the second output end of the master laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal; obtain N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal;Wherein, N is a positive integer and N≥2; Fourier transform is performed on the N first sampling results and the N second sampling results, a cross-correlation power spectrum density estimation operation is performed on the Fourier transform results, and the phase noise of the microwave signal to be measured is output according to the operation result. ;

[0008] According to a microwave source phase noise measurement method provided by the present invention, N≥100.

[0009] According to a microwave source phase noise measurement method provided by the present invention, Fourier transform is performed on the N first sampling results and the N second sampling results, and a cross-correlation power spectral density estimation operation is performed on the Fourier transform results, including: performing a cross-correlation power spectral density estimation operation on the N first sampling results and the N second sampling results based on a graphics processing unit GPU.

[0010] The present invention also provides a microwave source phase noise measurement device, comprising the following modules: a receiving module, a sampling module and a processing module.

[0011] A receiving module, for receiving a first microwave signal and a second microwave signal from a signal processing circuit; wherein the signal processing circuit comprises a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit comprises a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combining optical coupler and a second combining optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end by the first branch optical coupler, the first branch output end and The first output end of the first slave laser is connected to the input end of the first optical coupler, and the output end of the first optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second optical coupler, and the output end of the second optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the second frequency detector is connected to the input end of the second laser. The input end of the modulator is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combined optical coupler, a fourth combined optical coupler, a third photodetector and a fourth photodetector, and the input end of the phase modulator is connected to the master The second output end of the laser, the output end of the phase modulator is divided into a third branch output end and a fourth branch output end through a second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combiner optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combiner optical coupler, the output end of the third combiner optical coupler is connected to the third photodetector, and the output end of the fourth combiner optical coupler is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main optical signal outputted from the second output end of the master laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal.

[0012] The sampling module is used to obtain N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2.

[0013] The processing module is used to perform Fourier transform on the N first sampling results and the N second sampling results, perform cross-correlation power spectrum density estimation operation on the Fourier transform results, and output the phase noise of the microwave signal to be measured according to the operation results.

[0014] The present invention also provides a signal processing circuit applied to the above-mentioned microwave source phase noise measurement method, comprising: a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, wherein the heterodyne phase-locked subcircuit comprises a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combining optical coupler and a second combining optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end by the first branch optical coupler, the first branch output end and the first slave laser are connected to each other by the first branch optical coupler. The first output end of the laser is connected to the input end of the first optical coupler, and the output end of the first optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second optical coupler, and the output end of the second optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the first crystal oscillator; The input end is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combined optical coupler, a fourth combined optical coupler, a third photodetector and a fourth photodetector, and the input end of the phase modulator is connected to the master laser The second output end of the optical device, the output end of the phase modulator is divided into a third branch output end and a fourth branch output end through a second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combiner optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combiner optical coupler, the output end of the third combiner optical coupler is connected to the third photodetector, and the output end of the fourth combiner optical coupler is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main optical signal outputted from the second output end of the master laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal;The first microwave signal is used to be sampled to obtain N first sampling results, the second microwave signal is used to be sampled to obtain N second sampling results, the N first sampling results and the N second sampling results are used to perform Fourier transform to obtain Fourier transform results, and the Fourier transform results are used to perform cross-correlation power spectrum density estimation operation to obtain the phase noise of the microwave signal to be measured; wherein N is a positive integer and N≥2. ;

[0015] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, any of the above-mentioned microwave source phase noise measurement methods is implemented.

[0016] The present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, any of the microwave source phase noise measurement methods described above is implemented.

[0017] The present invention also provides a computer program product, comprising a computer program, and when the computer program is executed by a processor, the computer program implements any of the above-mentioned microwave source phase noise measurement methods.

[0018] In the microwave source phase noise measurement method, device, system and signal processing circuit provided by the present invention, the signal processing circuit includes a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit includes a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combining optical coupler and a second combining optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end by the first branch optical coupler, the first branch output end and the first The first output end of the slave laser is connected to the input end of the first combined optical coupler, and the output end of the first combined optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second combined optical coupler, and the output end of the second combined optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the second frequency detector is connected to the input end of the second slave laser. The input end of the first optical phase-locked loop is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combined optical coupler, a fourth combined optical coupler, a third photodetector and a fourth photodetector, and the input end of the phase modulator is connected to the master The second output end of the laser, the output end of the phase modulator is divided into a third branch output end and a fourth branch output end through a second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combiner optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combiner optical coupler, the output end of the third combiner optical coupler is connected to the third photodetector, and the output end of the fourth combiner optical coupler is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main optical signal outputted from the second output end of the master laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal;Based on the first microwave signal and the second microwave signal output by the signal processing circuit, by obtaining N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2; Fourier transform is performed on the N first sampling results and the N second sampling results, and the cross-correlation power spectrum density estimation operation is performed on the Fourier transform results, and the phase noise of the microwave signal to be measured is output according to the operation result. The signal processing circuit for microwave source phase noise measurement in the embodiment of the present invention has a simple structure, is relatively simple to manufacture and implement, is easy to produce and popularize, and the processing process of the first microwave signal and the second microwave signal output by the signal processing circuit is simple and efficient, thereby solving the defects of the prior art that the phase noise measurement process of the high-frequency signal in the microwave source phase noise measurement is relatively complicated and the noise measurement range is relatively limited, and the purpose of reducing the complexity of the high-frequency signal measurement process and improving the measurement speed while ensuring a high measurement sensitivity is achieved, and it is easy to produce and popularize. ; BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a structural schematic diagram of the microwave source phase noise measurement system provided by the present invention.

[0021] Figure 2 It is a structural schematic diagram of the microwave source phase noise measurement device provided by the present invention.

[0022] Figure 3 This is a diagram of the output results of the microwave source phase noise measurement system provided by the present invention.

[0023] Figure 4 It is a flow chart of the microwave source phase noise measurement method provided by the present invention.

[0024] Figure 5 The present invention is a schematic diagram of the circuit structure of a signal processing circuit for measuring microwave source phase noise.

[0025] Figure 6 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] First, the microwave source phase noise measurement system provided by the embodiment of the present invention is introduced. Figure 1 As shown, the microwave source phase noise measurement system 10 provided in the embodiment of the present invention includes a signal processing circuit 11 and a microwave source phase noise measurement device 12 .

[0028] Specifically, Figure 1 As shown, the signal processing circuit 11 includes a heterodyne phase-locked subcircuit 111 and a modulation down-conversion subcircuit 112 .

[0029] The heterodyne phase-locked subcircuit 111 includes a master laser 11101, a first photodetector 11102, a first frequency divider 11103, a first frequency detector 11104, a first crystal oscillator 11105, a first loop filter 11106, a first slave laser 11107, a second photodetector 11108, a second frequency divider 11109, a second frequency detector 11120, a second crystal oscillator 11121, a second loop filter 11122, a second slave laser 11123, a first branch optical coupler 11124, a first combining optical coupler 11125 and a second combining optical coupler 11126.

[0030] like Figure 1 As shown, the first output end of the master laser 11101 (i.e. Figure 1 The output end on the left side of the main laser 11101, Figure 1 ) is divided into two branch output ends by the first branch optical coupler 11124, and the two branch output ends are respectively the first branch output end (i.e. Figure 1 The output end corresponding to the first branch A11, Figure 1 not shown) and the second branch output terminal (i.e. Figure 1 The output end corresponding to the second branch A12, Figure 1 The first branch output end and the first output end of the first slave laser 11107 (i.e. Figure 1 The first output end from the left side of the laser 11107, Figure 1 ) is connected to the input end of the first optical coupler 11125 (located at Figure 1 On the right side of the first optical coupler 11125, Figure 1Not shown), the output end of the first optical coupler 11125 (located at Figure 1 On the left side of the first optical coupler 11125, Figure 1 11102, the first frequency divider 11103, the first frequency detector 11104 and the first loop filter 11106, and the input end of the first slave laser 11107 (located at Figure 1 The first one is from the upper side of the laser 11107, Figure 1 (not shown) are coupled to form a first optical phase-locked loop, wherein the input end of the first frequency detector 11104 is connected to the output end of the first crystal oscillator 11105.

[0031] In a specific implementation, a first driving circuit is provided in the first slave laser, and the output end of the first combining optical coupler 11125 is connected to the first driving circuit in the first slave laser 11107 through the first photodetector 11102, the first frequency divider 11103, the first frequency detector 11104 and the first loop filter 11106 in sequence to control the frequency of the first slave laser signal output by the first slave laser 11107.

[0032] The output terminal of the first crystal oscillator 11105 outputs a first reference signal, and the first reference signal is input into the first frequency detector 11104 as an input signal of the first phase frequency detector 11104. After the first reference signal output from the first crystal oscillator 11105 is input into the first phase frequency detector 11104, the frequency and phase are compared with the signal from the first frequency divider 11103 in the first phase frequency detector 11104, and the first phase frequency detector 11104 outputs a first control signal for controlling the first slave laser 11107, so as to control the frequency of the first slave laser signal output by the first slave laser 11107.

[0033] In the first optical phase-locked loop, the main optical signal outputted from the first output end of the main laser 11101 is divided into two identical main optical signals through the first branch optical coupler 11124, and the two identical main optical signals are outputted through the first branch A1 and the second branch A2 respectively. The main optical signal outputted from the first branch A1 and the first slave optical signal outputted from the first slave laser 11107 are inputted to the first optical combiner 11125. The first optical combiner 11125 combines the received main optical signal and the first slave optical signal, and outputs the first combined optical signal to the first photodetector 11102. The first photodetector 11102 converts the received first combined optical signal into a corresponding microwave signal. After the frequency division multiple is adjusted by the first frequency divider 11103 (the frequency division multiple is k), the microwave signal is outputted to the first frequency detector 11104. The frequency and phase difference of the microwave signal are monitored based on the first frequency detector 11104 and the first crystal oscillator 11105. The microwave signal outputted from the first frequency detector 11104 passes through the first loop filter 11106 and is inputted to the first slave laser 11107 as a feedback tuning signal of the first slave laser 1107, so that the second output end (i.e. Figure 1 The first output terminal from the right side of laser 11107, Figure 1 The first slave optical signal outputted from the master laser (not shown) is connected to the second output end (i.e. Figure 1 The output end on the right side of the main laser 11101, Figure 1 The difference between the frequencies of the first slave optical signal output from the second output end of the first slave laser 11107 and the main optical signal output from the second output end of the master laser 11101 is a set frequency, and the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency. That is to say, based on the setting of the first optical phase-locked loop, the difference between the frequencies of the first slave optical signal output from the second output end of the first slave laser 11107 and the main optical signal output from the second output end of the master laser 11101 is a fixed frequency, and the magnitude of the fixed frequency is equal to the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency.

[0034] See also Figure 1 It should be noted that the main optical signal outputted by the first output terminal on the left side of the master laser 11101 is the same as the main optical signal outputted by the second output terminal on the right side of the master laser 11101. The first slave optical signal outputted by the first output terminal on the left side of the first slave laser 11107 is the same as the first slave optical signal outputted by the second output terminal on the right side of the first slave laser 11107.

[0035] Please continue to see Figure 1 , the second branch A12 and the first output end of the second slave laser 11123 (ie Figure 1 The second output end from the left side of laser 11123, Figure 1) is connected to the input end of the second optical coupler 11126 (located at Figure 1 On the right side of the second optical coupler 11126, Figure 1 The output end of the second optical coupler 11126 (located at Figure 1 On the left side of the second optical coupler 11126, Figure 1 11108, the second frequency divider 11109, the second frequency detector 11120 and the second loop filter 11122, and the input end of the second slave laser 11123 (located at Figure 1 The second one is from the lower side of the laser 11123, Figure 1 (not shown) to form a second optical phase-locked loop, wherein the input end of the second frequency detector 11120 is connected to the output end of the second crystal oscillator 11121.

[0036] Similar to the first slave laser, the second slave laser is provided with a second driving circuit, and the output end of the output end of the second combining optical coupler 11126 is connected to the second driving circuit in the second slave laser 11123 through the second photodetector 11108, the second frequency divider 11109, the second frequency detector 11120 and the second loop filter 11122 in sequence to control the frequency of the second slave laser signal output by the second slave laser 11123.

[0037] The output end of the second crystal oscillator 11121 outputs a second reference signal, and the second reference signal is input into the second frequency detector 11120 as an input signal of the second frequency detector 11120. After the second reference signal output from the second crystal oscillator 11121 is input into the second frequency detector 11120, the frequency and phase are compared with the signal from the second frequency divider 11109 in the second frequency detector 11120, and the second frequency detector 11120 outputs a second control signal for controlling the second slave laser 11123, so as to control the frequency of the second slave laser signal output by the second slave laser 11123.

[0038] In the second optical phase-locked loop, the main optical signal output on the second branch A2 and the second slave optical signal output on the second slave laser 11123 are input to the second combining optical coupler 11126, the second combining optical coupler 11126 combines the received main optical signal and the first slave optical signal, and outputs the second combined optical signal to the second photodetector 11108, the second photodetector 11108 converts the received second combined optical signal into a corresponding microwave signal, and the microwave signal is transmitted to the second frequency divider (frequency division multiplier). The microwave signal is output to the second frequency detector 11120 after the frequency division multiple is adjusted by the second frequency detector 11109. The frequency and phase difference of the microwave signal are monitored based on the second frequency detector 11120 and the second crystal oscillator 11121. The microwave signal output by the second frequency detector 11120 is input to the second slave laser 11123 after passing through the second loop filter 11122, so as to serve as the feedback tuning signal of the second slave laser 11123, so that the second output end (located at Figure 1 The second one is on the right side of the laser 11123, Figure 1 The difference between the frequency of the second slave optical signal output from the second output end A2 of the master laser 11101 (not shown) and the frequency of the master optical signal output from the second output end A2 of the master laser 11101 is a set frequency, and the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency. In other words, based on the setting of the second optical phase-locked loop, the difference between the frequency of the second slave optical signal output from the second output end of the second slave laser 11123 and the frequency of the master optical signal output from the second output end of the master laser 11101 is a fixed frequency, and the magnitude of the fixed frequency is equal to the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency.

[0039] It should be noted that the second slave optical signal output from the first output end of the second slave laser 11123 is the same as the second slave optical signal output from the second output end of the second slave laser 11123 .

[0040] In a specific implementation, the master laser 11101 may be a continuous wave (CW) laser, such as a CW narrow line width laser. The first slave laser 11107 and the second slave laser 11123 may be, for example, tunable narrow line width lasers.

[0041] The following introduces the principle of using the first optical phase-locked loop to make the frequency difference between the main optical signal output by the master laser and the first slave optical signal output by the first slave laser equal to the set frequency, and the principle of using the second optical phase-locked loop to make the frequency difference between the main optical signal output by the master laser and the second slave optical signal output by the second slave laser equal to the set frequency.

[0042] Specifically, in the heterodyne phase-locked subcircuit 11, the main optical signal outputted from the first output terminal and the second output terminal of the main laser 11101 is It can be calculated by the following formula: ; in, is the electric field amplitude of the main light signal, is the relative intensity noise of the main light signal, is the angular frequency of the main optical signal output by the main laser, is the phase jitter of the main optical signal output by the main laser, Represents the phase of a complex number.

[0043] After the heterodyne phase-locked subcircuit, the first slave optical signal output from the first slave laser 11107 and the second slave optical signal outputted by the second slave laser 11123 It can be calculated by the following formula: ; ; in, is the relative intensity noise of the first slave optical signal output by the first slave laser 11107, is the electric field amplitude of the first slave optical signal, is the angular frequency of the first slave optical signal output from the first slave laser 11107, is the phase jitter of the first slave optical signal output by the first slave laser 11107; is the relative intensity noise of the second slave optical signal output by the second slave laser 11123, is the electric field amplitude of the second slave optical signal, is the angular frequency of the second slave optical signal output from the second slave laser 11123, is the phase jitter of the second slave optical signal output by the second slave laser 11123.

[0044] After the first optical phase-locked loop and the second optical phase-locked loop are phase-locked, the angular frequency can satisfy the following relationship: the angular frequency of the first microwave signal , the angular frequency of the second microwave signal ;in, , is the angular frequency of the second crystal oscillator, k is the frequency division multiple of the first optical phase-locked loop and the second optical phase-locked loop; the phase jitter can satisfy the following relationship: the phase jitter of the first microwave signal , the phase jitter of the second microwave signal ;in, is the phase jitter of the first crystal oscillator, For the phase jitter of the second crystal oscillator, combined Figure 1It can be seen that by controlling the frequency division multiple k in the first optical phase-locked loop and the second optical phase-locked loop, the frequency difference between the main optical signal output by the master laser and the first slave optical signal output by the first slave laser after phase locking can be the sum of the microwave signal frequency of the microwave signal to be measured and a set intermediate frequency, that is, ;in, , is the microwave signal frequency of the microwave signal to be measured, The intermediate frequency is set.

[0045] It should be noted that the set intermediate frequency can be set by those skilled in the art according to actual conditions, and the embodiment of the present invention is not limited to this.

[0046] Please continue to see Figure 1 The modulation down-conversion subcircuit 112 includes a phase modulator 11201, a second branch optical coupler 11202, a third combined optical coupler 11203, a fourth combined optical coupler 11204, a third photodetector 11205 and a fourth photodetector 11206. The input end of the phase modulator 11201 (located at Figure 1 On the left side of the phase modulator 11201, Figure 1 The output end of the phase modulator 11201 (not shown) is connected to the second output end of the master laser 11101, and the output end of the phase modulator 11201 (located at Figure 1 On the right side of the phase modulator 11201, Figure 1 ) is divided into a third branch output terminal (i.e. Figure 1 The output end corresponding to the third branch D11, Figure 1 not shown) and the fourth branch output terminal (i.e. Figure 1 The output end corresponding to the fourth branch D12, Figure 1 The output end of the third branch and the second output end of the first slave laser 11107 are connected to the input end of the third combining optical coupler 11203 (located at Figure 1 On the left side of the third optical coupler 11203, Figure 1 The fourth branch output end and the second output end of the second slave laser 11123 are connected to the input end of the fourth combining optical coupler 11204 (located at Figure 1 On the left side of the fourth optical coupler 11204, Figure 1 The output end of the third optical coupler 11203 (located at Figure 1 On the right side of the third optical coupler 11203, Figure 1 The output end of the fourth optical coupler 11204 (located at Figure 1 On the right side of the fourth optical coupler 11204, Figure 1A fourth photodetector 11206 is connected (not shown).

[0047] like Figure 1 As shown, the phase modulator 11201 is used to receive the microwave signal to be measured and modulate it on the main light signal output from the second output end of the main laser 11101, the third photodetector 11205 is used to output the first microwave signal, and the fourth photodetector 11206 is used to output the second microwave signal.

[0048] See also Figure 1 , the main optical signal output from the second output end of the master laser 11101 is input to the phase modulator 11201, and the phase modulator 11201 also receives the microwave signal to be measured. The phase modulator 11201 modulates the microwave signal to be measured onto the main optical signal received by the phase modulator 11201, and outputs the modulated optical signal; the modulated optical signal is output from the third branch output end and the fourth branch output end respectively after passing through the second branch optical coupler 11202, and the modulated optical signal output from the third branch D11 and the first slave optical signal output from the second output end of the first slave laser are input to the third combining optical coupler 11203 for combination, and the third combining optical coupler 11203 combines The combined third combined optical signal is output to the third photodetector 11205. The third photodetector 11205 converts the received third combined optical signal into a corresponding microwave signal, obtains a first microwave signal and outputs it; the modulated optical signal on the fourth branch D12 and the second slave optical signal output from the second output end of the second slave laser are input to the fourth combined optical coupler 11204 for combination. The fourth combined optical coupler 11204 outputs the combined fourth combined optical signal to the fourth photodetector 11206. The fourth photodetector 11206 converts the received fourth combined optical signal into a corresponding microwave signal, obtains a second microwave signal and outputs it. In this way, the first microwave signal and the second microwave signal can be obtained. Based on the first microwave signal and the second microwave signal, the phase noise of the microwave signal to be measured can be obtained.

[0049] The following describes a principle of obtaining the phase noise of the microwave signal to be measured based on the first microwave signal and the second microwave signal.

[0050] First, let's introduce the process of obtaining the expressions of the first microwave signal and the second microwave signal. Figure 1 In the modulation down-conversion subcircuit 112, the phase modulator 11201 receives the microwave signal to be measured, and modulates the microwave signal to be measured onto the main optical signal output by the main laser. The modulated optical signal It can be expressed by the following formula: ; in, is the insertion loss of the phase modulator 11201, is the modulation coefficient of the phase modulator, , is the modulation signal amplitude, is the phase modulator half-wave voltage, is the angular frequency of the microwave signal to be measured, is the phase jitter of the microwave signal to be measured. The negative first-order sideband expression can be obtained from the Jacobi-Anger expansion as follows: .

[0051] Wherein, J1 is a first-order Bessel function.

[0052] Based on the above calculation results, the photocurrent signal (first microwave signal) output by the third photodetector 11205 is as follows: ； .

[0053] Similarly, the photocurrent signal (second microwave signal) output by the fourth photodetector 11206 is as follows: .

[0054] After introducing the process of obtaining the expressions of the first microwave signal and the second microwave signal, the process of obtaining the phase noise of the microwave signal to be measured based on the first microwave signal and the second microwave signal is introduced next.

[0055] Please continue to see Figure 1 In the embodiment of the present invention, the microwave source phase noise measuring device 12 receives the first microwave signal and the second microwave signal, and obtains the phase noise of the microwave signal to be measured according to the first microwave signal and the second microwave signal.

[0056] like Figure 2 As shown, the microwave source phase noise measurement device 200 includes a receiving module 201 , a sampling module 202 and a processing module 203 .

[0057] The receiving module 201 is used to receive the first microwave signal and the second microwave signal from the signal processing circuit.

[0058] Specifically, the signal processing circuit, namely the signal processing circuit 11 in the above embodiment, its circuit structure, and the process of obtaining the first microwave signal and the second microwave signal can be specifically referred to the corresponding description in the above embodiment, which will not be repeated here.

[0059] The sampling module 22 is used to obtain N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2.

[0060] like Figure 1 As shown, in the microwave source phase noise measuring device 12, the first microwave signal can be sampled based on the ADC to obtain N first sampling results, and the second microwave signal can be sampled based on the ADC to obtain N second sampling results.

[0061] In some embodiments, N≥100 to ensure that the phase noise obtained in the subsequent module (corresponding to the processing module 23 ) has higher accuracy.

[0062] The processing module 23 is used to perform Fourier transform on the N first sampling results and the N second sampling results, perform cross-correlation power spectrum density estimation operation on the Fourier transform results, and output the phase noise of the microwave signal to be measured according to the operation results.

[0063] like Figure 1 As shown, the microwave source phase noise measuring device 12 can perform Fourier transform (FFT) on the N first sampling results and the N second sampling results obtained by ADC sampling, and perform digital signal processing (DSP) on the Fourier transform results.

[0064] When performing digital signal processing on the Fourier transform result, a cross-correlation power spectrum density estimation operation can be performed on the N first sampling results and the N second sampling results based on a graphics processing unit (GPU). For the Mth first sampling result and the Mth second sampling result obtained by sampling at the same time, N≥M≥1, the Mth first sampling result and the Mth second sampling result are matched to obtain a pair of sampling pairs, and a cross-correlation power spectrum density estimation operation is performed on the sampling pair to obtain the operation result corresponding to the sampling pair. The calculation of each sampling pair is recorded as one calculation. For the N first sampling results and the N second sampling results, N sampling pairs can be obtained. The parallel calculation of the N sampling pairs based on the graphics processing unit GPU can improve the operation efficiency.

[0065] Of course, it is understandable that the cross-correlation power spectrum density estimation operation can be performed on the N first sampling results and the N second sampling results in other ways (such as a central processing unit (CPU)) to obtain the operation result.

[0066] It should be noted that the phase noise of the microwave source to be measured is contained in the phase of the first microwave signal and the second microwave signal. After ADC sampling, since the amplitude of the electrical signal is a slow variable and the signal is a single frequency within a measurement period, the phase of the first microwave signal and the second microwave signal can be solved by Hilbert transform. After removing the phase of the intermediate frequency signal (i.e., the signal corresponding to the intermediate frequency set above) from the obtained phase, the obtained phase includes the phase of the microwave signal to be measured, the noise term (i.e., the phase jitter of the microwave signal to be measured), the phase jitter of the first microwave signal , Phase jitter of the second microwave signal , other phase noise introduced by the first optical phase-locked loop and the second optical phase-locked loop, noise introduced by photodetectors (including the first photodetector, the second photodetector, the third photodetector and the fourth photodetector), quantization noise and aperture jitter noise generated by ADC, etc. By performing power spectral density estimation operation on the first microwave signal and the second microwave signal through cross-correlation technology, non-correlated noise can be offset. As the number of cross-correlations increases to m times (ie, N=m), the power spectral density mean of non-correlated interference terms decreases. Therefore, the noise of the first optical phase-locked loop, the noise of the second optical phase-locked loop, the noise of the photodetector, and the noise introduced by the ADC can be effectively suppressed, thereby reducing the noise floor and improving the measurement sensitivity.

[0067] Finally, if Figure 1 Based on the calculation result, the calculation result is used to generate the corresponding phase noise image for display. For example, if N=10 and N=100, the output can be as follows: Figure 3 The phase noise measurement results are shown. Figure 3 The SUT phase noise here refers to the phase noise.

[0068] In the embodiment of the present invention, since the microwave signal to be measured is loaded on the optical signal for measurement, the higher frequency range of the optical signal itself can break through the current limitation that the noise of high-frequency signals cannot be measured, and the noise measurement range is widened; at the same time, the signal processing circuit for microwave source phase noise measurement in the embodiment of the present invention has a simple structure, and is relatively simple to manufacture and implement, and is easy to produce and popularize.

[0069] In the microwave source phase noise measurement system and device provided by the present invention, the signal processing circuit includes a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit includes a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combined optical coupler and a second combined optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end by the first branch optical coupler, the first branch output end and the first slave laser are connected to each other through the first branch optical coupler. The output end is connected to the input end of the first optical coupler, and the output end of the first optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second optical coupler, and the output end of the second optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the second crystal oscillator. The output end of the second crystal oscillator is connected; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combined optical coupler, a fourth combined optical coupler, a third photodetector and a fourth photodetector, and the input end of the phase modulator is connected to the master laser The output end of the phase modulator is divided into a third branch output end and a fourth branch output end through a second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combining optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combining optical coupler, the output end of the third combining optical coupler is connected to the third photodetector, and the output end of the fourth combining optical coupler is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main optical signal outputted from the second output end of the master laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal;Based on the first microwave signal and the second microwave signal output by the signal processing circuit, by obtaining N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2; Fourier transform is performed on the N first sampling results and the N second sampling results, and the cross-correlation power spectrum density estimation operation is performed on the Fourier transform results, and the phase noise of the microwave signal to be measured is output according to the operation result. The signal processing circuit for microwave source phase noise measurement in the embodiment of the present invention has a simple structure, is relatively simple to manufacture and implement, is easy to produce and popularize, and the processing process of the first microwave signal and the second microwave signal output by the signal processing circuit is simple and efficient, thereby solving the defects of the prior art that the phase noise measurement process of the high-frequency signal in the microwave source phase noise measurement is relatively complicated and the noise measurement range is relatively limited, and the purpose of reducing the complexity of the high-frequency signal measurement process and improving the measurement speed while ensuring a high measurement sensitivity is achieved, and it is easy to produce and popularize. ;

[0070] The microwave source phase noise measurement method provided by the present invention is described below. The microwave source phase noise measurement described below and the microwave source phase noise measurement device described above can correspond to each other.

[0071] Figure 4 FIG. 1 is a flow chart of a microwave source phase noise measurement method provided by an embodiment of the present invention. Figure 4 As shown, the method includes the following S410~S430.

[0072] S410: Receive a first microwave signal and a second microwave signal from a signal processing circuit.

[0073] The signal processing circuit includes a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit includes a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combined optical coupler and a second combined optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end through the first branch optical coupler, the first branch output end and the first output end of the first slave laser are connected to the input end of the first combined optical coupler The output end of the first optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second optical coupler, and the output end of the second optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the second crystal oscillator. connection; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combined optical coupler, a fourth combined optical coupler, a third photodetector and a fourth photodetector, and the input end of the phase modulator is connected to the second output end of the master laser The output end of the phase modulator is divided into a third branch output end and a fourth branch output end through a second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combiner optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combiner optical coupler, the output end of the third combiner optical coupler is connected to the third photodetector, and the output end of the fourth combiner optical coupler is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main optical signal outputted from the second output end of the master laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal.

[0074] S420: Obtain N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2.

[0075] S430: Perform Fourier transform on the N first sampling results and the N second sampling results, perform cross-correlation power spectrum density estimation operation on the Fourier transform results, and output the phase noise of the microwave signal to be measured according to the operation results.

[0076] In the microwave source phase noise measurement method provided by the present invention, the signal processing circuit includes a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit includes a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combined optical coupler and a second combined optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end by the first branch optical coupler, the first branch output end and the first output end of the first slave laser are connected to the input end of the first combined optical coupler, The output end of the first combined optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second combined optical coupler, and the output end of the second combined optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the second frequency detector is coupled to the second crystal oscillator; based on the first optical phase-locked loop, the first slave laser outputted from the second output end of the first slave laser The difference between the frequency of the optical signal and the main optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the difference between the frequency of the main optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combined optical coupler, a fourth combined optical coupler, a third photodetector and a fourth photodetector, the input end of the phase modulator is connected to the second output end of the master laser, the output end of the phase modulator is divided into a third branch output end and a fourth branch output end through the second branch optical coupler, the third branch output end and the first slave laser are connected to each other. The second output end of the laser is connected to the input end of the third combined optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combined optical coupler, the output end of the third combined optical coupler is connected to the third photodetector, and the output end of the fourth combined optical coupler is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main optical signal output by the second output end of the master laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal; based on the first microwave signal and the second microwave signal output by the signal processing circuit, by acquiring N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal;Wherein, N is a positive integer and N≥2; Fourier transform is performed on the N first sampling results and the N second sampling results, and a cross-correlation power spectrum density estimation operation is performed on the Fourier transform results, and the phase noise of the microwave signal to be measured is output according to the operation result. The signal processing circuit for microwave source phase noise measurement in the embodiment of the present invention has a simple structure, is relatively simple to manufacture and implement, is easy to produce and popularize, and the processing process of the first microwave signal and the second microwave signal output by the signal processing circuit is simple and efficient, thereby solving the defects of the prior art that the phase noise measurement process of the high-frequency signal in the microwave source phase noise measurement is relatively complicated and the noise measurement range is relatively limited, and the purpose of reducing the complexity of the high-frequency signal measurement process and improving the measurement speed while ensuring a high measurement sensitivity is achieved, and it is easy to produce and popularize. ;

[0077] The present invention also provides a signal processing circuit. Figure 5 As shown, the signal processing circuit 11 provided by the present invention includes a heterodyne phase-locked subcircuit 111 and a modulation down-conversion subcircuit 112 .

[0078] The heterodyne phase-locked subcircuit 111 includes a master laser 11101, a first photodetector 11102, a first frequency divider 11103, a first frequency detector 11104, a first crystal oscillator 11105, a first loop filter 11106, a first slave laser 11107, a second photodetector 11108, a second frequency divider 11109, a second frequency detector 11120, a second crystal oscillator 11121, a second loop filter 11122, a second slave laser 11123, a first branch optical coupler 11124, a first combining optical coupler 11125 and a second combining optical coupler 11126.

[0079] The modulation down-conversion subcircuit 112 includes a phase modulator 11201 , a second branching optical coupler 11202 , a third combining optical coupler 11203 , a fourth combining optical coupler 11204 , a third photodetector 11205 and a fourth photodetector 11206 .

[0080] The connection mode of each component in the heterodyne phase-locked subcircuit 111 and the modulation down-conversion subcircuit 112 and the signal processing process can be found in the introduction part of the signal processing circuit 11 in the above-mentioned embodiment of the microwave source phase noise measurement system, and will not be repeated here.

[0081] The third photodetector 11205 is used to output a first microwave signal, and the fourth photodetector 11206 is used to output a second microwave signal. The first microwave signal is used to be sampled to obtain N first sampling results, and the second microwave signal is used to be sampled to obtain N second sampling results. The N first sampling results and the N second sampling results are used to perform Fourier transform to obtain Fourier transform results, and the Fourier transform results are used to perform a cross-correlation power spectral density estimation operation to obtain the phase noise of the microwave signal to be measured; wherein N is a positive integer and N≥2.

[0082] The present invention provides a signal processing circuit for measuring microwave source phase noise, wherein the signal processing circuit comprises a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, wherein the heterodyne phase-locked subcircuit comprises a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combining optical coupler and a second combining optical coupler, wherein a first output end of the master laser is divided into a first branch output end and a second branch output end by the first branch optical coupler, and a first branch output end and a first slave laser are connected to each other. The first output end is connected to the input end of the first optical coupler, and the output end of the first optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second optical coupler, and the output end of the second optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the first crystal oscillator; The first optical phase-locked loop is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combined optical coupler, a fourth combined optical coupler, a third photodetector and a fourth photodetector, and the input end of the phase modulator is connected to the master laser The output end of the phase modulator is divided into a third branch output end and a fourth branch output end through a second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combining optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combining optical coupler, the output end of the third combining optical coupler is connected to the third photodetector, and the output end of the fourth combining optical coupler is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main optical signal outputted from the second output end of the master laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal;Based on the first microwave signal and the second microwave signal output by the signal processing circuit, by obtaining N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2; Fourier transform is performed on the N first sampling results and the N second sampling results, and the cross-correlation power spectrum density estimation operation is performed on the Fourier transform results, and the phase noise of the microwave signal to be measured is output according to the operation result. The signal processing circuit for microwave source phase noise measurement in the embodiment of the present invention has a simple structure, is relatively simple to manufacture and implement, is easy to produce and popularize, and the processing process of the first microwave signal and the second microwave signal output by the signal processing circuit is simple and efficient, thereby solving the defects of the prior art that the phase noise measurement process of the high-frequency signal in the microwave source phase noise measurement is relatively complicated and the noise measurement range is relatively limited, and the purpose of reducing the complexity of the high-frequency signal measurement process and improving the measurement speed while ensuring a high measurement sensitivity is achieved, and it is easy to produce and popularize. ;

[0083] Figure 6 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 6As shown, the electronic device may include: a processor (processor) 610 , a communication interface (Communications Interface) 620 , a memory (memory) 630 and a communication bus 640 , wherein the processor 610 , the communication interface 620 , and the memory 630 communicate with each other through the communication bus 640 . The processor 610 can call the logic instructions in the memory 630 to execute the microwave source phase noise measurement method, which includes: receiving a first microwave signal and a second microwave signal from a signal processing circuit; wherein the signal processing circuit includes a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit includes a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combining optical coupler and a second combining optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end through the first branch optical coupler, the first branch output end and the first output end of the first slave laser are connected to the input end of the first combining optical coupler, and the output end of the first combining optical coupler is sequentially transmitted through the first photodetector, the first frequency divider, the first frequency detector and the first phase detector. A first loop filter is connected to the input end of the first slave laser to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second combined optical coupler, and the output end of the second combined optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the difference in frequency between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the difference in frequency between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency;The modulation down-conversion subcircuit comprises a phase modulator, a second branch optical coupler, a third combining optical coupler, a fourth combining optical coupler, a third photodetector and a fourth photodetector, the input end of the phase modulator is connected to the second output end of the master laser, the output end of the phase modulator is divided into a third branch output end and a fourth branch output end through the second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combining optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combining optical coupler, the output end of the third combining optical coupler is connected to the third photodetector, and the fourth combining optical coupler is connected to the input end of the fourth combining optical coupler. The output end of the combiner is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main light signal outputted from the second output end of the main laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal; N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal are obtained; wherein N is a positive integer and N≥2; Fourier transform is performed on the N first sampling results and the N second sampling results, and a cross-correlation power spectrum density estimation operation is performed on the Fourier transform result, and the phase noise of the microwave signal to be measured is outputted according to the operation result. ;

[0084] In addition, the logic instructions in the above-mentioned memory 630 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0085] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the microwave source phase noise measurement method provided by the above methods, and the method includes: receiving a first microwave signal and a second microwave signal from a signal processing circuit; wherein the signal processing circuit includes a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, and the heterodyne phase-locked subcircuit includes a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, A second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combining optical coupler and a second combining optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end through the first branch optical coupler, the first branch output end and the first output end of the first slave laser are connected to the input end of the first combining optical coupler, the output end of the first combining optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence, to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the first photodetector, the first frequency divider, the first frequency detector and the first loop filter, to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the first photodetector, the first frequency divider, the first frequency detector and the first loop filter, to form a first optical phase-locked loop, The input end of the two-way optical coupler and the output end of the second-way optical coupler are connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the microwave signal frequency of the microwave signal to be measured. The modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combining optical coupler, a fourth combining optical coupler, a third photodetector and a fourth photodetector, the input end of the phase modulator is connected to the second output end of the master laser, the output end of the phase modulator is divided into a third branch output end and a fourth branch output end through the second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combining optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combining optical coupler, the output end of the third combining optical coupler is connected to the third photodetector, and the output end of the fourth combining optical coupler is connected to the fourth photodetector;The phase modulator is used to receive the microwave signal to be measured and modulate it on the main light signal output from the second output end of the main laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal; obtain N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2; perform Fourier transform on the N first sampling results and the N second sampling results, perform cross-correlation power spectrum density estimation operation on the Fourier transform results, and output the phase noise of the microwave signal to be measured according to the operation result. ;

[0086] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to perform the microwave source phase noise measurement method provided by the above methods, the method comprising: receiving a first microwave signal and a second microwave signal from a signal processing circuit; wherein the signal processing circuit comprises a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit comprises a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, , a first branch optical coupler, a first combining optical coupler, and a second combining optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end through the first branch optical coupler, the first branch output end and the first output end of the first slave laser are connected to the input end of the first combining optical coupler, the output end of the first combining optical coupler is sequentially coupled with the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second combining optical coupler, and the second combining optical coupler is connected to the first output end of the second slave laser. The output end of the optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency The sum of frequencies; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combining optical coupler, a fourth combining optical coupler, a third photodetector and a fourth photodetector, the input end of the phase modulator is connected to the second output end of the master laser, the output end of the phase modulator is divided into a third branch output end and a fourth branch output end through the second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combining optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combining optical coupler, the output end of the third combining optical coupler is connected to the third photodetector, and the output end of the fourth combining optical coupler is connected to the fourth photodetector;The phase modulator is used to receive the microwave signal to be measured and modulate it on the main light signal output from the second output end of the main laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal; obtain N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2; perform Fourier transform on the N first sampling results and the N second sampling results, perform cross-correlation power spectrum density estimation operation on the Fourier transform results, and output the phase noise of the microwave signal to be measured according to the operation result. ;

[0087] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0088] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A microwave source phase noise measurement method, characterized in that: include: Receive a first microwave signal and a second microwave signal from a signal processing circuit; wherein the signal processing circuit includes a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit includes a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combining optical coupler and a second combining optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end by the first branch optical coupler, the first branch output end and The first output end of the first slave laser is connected to the input end of the first optical combiner, and the output end of the first optical combiner is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the second branch output end and the first output end of the second slave laser are connected to the input end of the second optical combiner, and the output end of the second optical combiner is connected to the input end of the second optical combiner through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence. , connected to the input end of the second slave laser to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a first Two branch optical couplers, a third combining optical coupler, a fourth combining optical coupler, a third photodetector and a fourth photodetector, the input end of the phase modulator is connected to the second output end of the master laser, the output end of the phase modulator is divided into a third branch output end and a fourth branch output end through the second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combining optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combining optical coupler, the output end of the third combining optical coupler is connected to the third photodetector, and the output end of the fourth combining optical coupler is connected to the fourth photodetector;The phase modulator is used to receive the microwave signal to be measured and modulate it on the main light signal outputted from the second output end of the main laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal; Acquire N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2; Performing Fourier transform on the N first sampling results and the N second sampling results, performing cross-correlation power spectrum density estimation operation on the Fourier transform results, and outputting the phase noise of the microwave signal to be measured according to the operation results.

2. The microwave source phase noise measurement method according to claim 1, characterized in that: N≥100。 3. The microwave source phase noise measurement method according to claim 1 or 2, characterized in that: The performing Fourier transform on the N first sampling results and the N second sampling results, and performing a cross-correlation power spectrum density estimation operation on the Fourier transform results, comprises: A cross-correlation power spectrum density estimation operation is performed on the N first sampling results and the N second sampling results based on a graphics processing unit (GPU).

4. A microwave source phase noise measurement device, characterized in that: include: A receiving module, for receiving a first microwave signal and a second microwave signal from a signal processing circuit; wherein the signal processing circuit comprises a heterodyne phase-locked subcircuit and a modulation down-conversion subcircuit, the heterodyne phase-locked subcircuit comprises a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combining optical coupler and a second combining optical coupler, the first output end of the master laser is divided into a first branch output end and a second branch output end by the first branch optical coupler, the first branch The output end of the second branch and the first output end of the first slave laser are connected to the input end of the first combining optical coupler, and the output end of the first combining optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the output end of the first crystal oscillator; the output end of the second branch and the first output end of the second slave laser are connected to the input end of the second combining optical coupler, and the output end of the second combining optical coupler is connected to the input end of the first slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence. A filter is connected to the input end of the second slave laser to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the master optical signal output from the second output end of the master laser is a set frequency; based on the second optical phase-locked loop, the frequency difference between the master optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; the modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combining optical coupler, a fourth combining optical coupler, a third photodetector and a fourth photodetector, the input end of the phase modulator is connected to the second output end of the master laser, the output end of the phase modulator is divided into a third branch output end and a fourth branch output end through the second branch optical coupler, the third branch output end and the second output end of the first slave laser are connected to the input end of the third combining optical coupler, the fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combining optical coupler, the output end of the third combining optical coupler is connected to the third photodetector, and the output end of the fourth combining optical coupler is connected to the fourth photodetector;The phase modulator is used to receive the microwave signal to be measured and modulate it on the main light signal outputted from the second output end of the main laser, the third photodetector is used to output the first microwave signal, and the fourth photodetector is used to output the second microwave signal; A sampling module, used to obtain N first sampling results of sampling the first microwave signal and N second sampling results of sampling the second microwave signal; wherein N is a positive integer and N≥2; A processing module is used to perform Fourier transform on the N first sampling results and the N second sampling results, perform cross-correlation power spectrum density estimation operation on the Fourier transform results, and output the phase noise of the microwave signal to be measured according to the operation results.

5. The microwave source phase noise measurement device according to claim 4, characterized in that: N≥100。 6. A signal processing circuit applied to the microwave source phase noise measurement method according to any one of claims 1 to 3, characterized in that: include: Heterodyne phase-locked subcircuit and modulation down-conversion subcircuit, wherein: The heterodyne phase-locked subcircuit comprises a master laser, a first photodetector, a first frequency divider, a first frequency detector, a first crystal oscillator, a first loop filter, a first slave laser, a second photodetector, a second frequency divider, a second frequency detector, a second crystal oscillator, a second loop filter, a second slave laser, a first branch optical coupler, a first combining optical coupler and a second combining optical coupler, wherein the first output end of the master laser is divided into a first branch output end and a second branch output end through the first branch optical coupler, the first branch output end and the first output end of the first slave laser are connected to the input end of the first combining optical coupler, the output end of the first combining optical coupler is connected to the input end of the first slave laser through the first photodetector, the first frequency divider, the first frequency detector and the first loop filter in sequence, so as to form a first optical phase-locked loop, wherein the input end of the first frequency detector is connected to the first crystal oscillator. the output end of the second branch and the first output end of the second slave laser are connected to the input end of the second optical coupler, the output end of the second optical coupler is connected to the input end of the second slave laser through the second photodetector, the second frequency divider, the second frequency detector and the second loop filter in sequence, to form a second optical phase-locked loop, wherein the input end of the second frequency detector is connected to the output end of the second crystal oscillator; based on the first optical phase-locked loop, the frequency difference between the first slave optical signal output from the second output end of the first slave laser and the main optical signal output from the second output end of the master laser is the set frequency; based on the second optical phase-locked loop, the frequency difference between the main optical signal output from the second output end of the master laser and the second slave optical signal output from the second output end of the second slave laser is the set frequency; the set frequency is the sum of the microwave signal frequency of the microwave signal to be measured and the set intermediate frequency; The modulation down-conversion subcircuit includes a phase modulator, a second branch optical coupler, a third combining optical coupler, a fourth combining optical coupler, a third photodetector and a fourth photodetector. The input end of the phase modulator is connected to the second output end of the master laser. The output end of the phase modulator is divided into a third branch output end and a fourth branch output end through the second branch optical coupler. The third branch output end and the second output end of the first slave laser are connected to the input end of the third combining optical coupler. The fourth branch output end and the second output end of the second slave laser are connected to the input end of the fourth combining optical coupler. The output end of the third combining optical coupler is connected to the third photodetector. The output end of the fourth combining optical coupler is connected to the third photodetector. The first output terminal is connected to the fourth photodetector; the phase modulator is used to receive the microwave signal to be measured and modulate it on the main light signal outputted from the second output terminal of the main laser; the third photodetector is used to output the first microwave signal; and the fourth photodetector is used to output the second microwave signal; the first microwave signal is used to be sampled to obtain N first sampling results, and the second microwave signal is used to be sampled to obtain N second sampling results, the N first sampling results and the N second sampling results are used to perform Fourier transform to obtain Fourier transform results, and the Fourier transform results are used to perform a cross-correlation power spectral density estimation operation to obtain the phase noise of the microwave signal to be measured; wherein N is a positive integer and N≥2.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the microwave source phase noise measurement method according to any one of claims 1 to 3 is implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the microwave source phase noise measurement method according to any one of claims 1 to 3 is implemented.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the microwave source phase noise measurement method according to any one of claims 1 to 3 is implemented.

10. A microwave source phase noise measurement system, characterized in that: include: A microwave source phase noise measurement device as described in any one of claims 4-5 and a signal processing circuit as described in claim 6.

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