A machine learning based microwave frequency measurement system and method

Abstract

The present disclosure provides a microwave frequency measurement system, comprising: an amplitude measurement module, configured to modulate a to-be-measured microwave signal on a continuous wide-spectrum light wave signal to generate a modulated signal, and divide the modulated signal into an upper modulated signal and a lower modulated signal, and convert the upper modulated signal and the lower modulated signal into a first electrical signal and a second electrical signal after introducing a first delay and a second delay, respectively; and a frequency measurement module, configured to calculate a power comparison value of the first electrical signal and the second electrical signal, and obtain a frequency of the to-be-measured microwave signal based on a preset mapping relationship between the power comparison value and the frequency of the microwave signal. The present disclosure removes difficult-to-measure parameters and suppresses common-mode noise by constructing a power comparison value, and suppresses differential-mode noise in a preset power comparison function by a machine learning algorithm, thereby improving the accuracy of frequency measurement.

Description

Technical Field

[0001] This disclosure relates to the field of microwave photonics technology, and more specifically, to a machine learning-based reconfigurable microwave frequency measurement device and method. Background Technology

[0002] In recent years, with the development of microwave photonics technology, microwave frequency measurement systems have received widespread research and attention. These systems have broad applications in radar, communications, and electronic warfare.

[0003] The principle of a microwave frequency measurement system is to map the microwave frequency to be measured into a parameter that is relatively easy to measure in a microwave frequency measurement device. The frequency of the microwave signal is obtained by relying on the mapping relationship between frequency and measurable parameter.

[0004] Microwave frequency measurement systems based on frequency-power mapping map the frequency information of a microwave signal to its power information. However, in practical applications, power jitter in the measured microwave signal generates common-mode noise, affecting measurement accuracy. Simultaneously, differential-mode noise is generated during the transmission of the measured microwave signal within the system due to optical link jitter. Therefore, building a microwave frequency measurement system capable of simultaneously suppressing both common-mode and differential-mode noise is crucial. Summary of the Invention

[0005] In view of this, the present disclosure provides a microwave frequency measurement system, comprising: an amplitude measurement module, configured to modulate the microwave signal to be measured onto a continuous broadband optical signal to generate a modulation signal, and to divide the modulation signal into an upper modulation signal and a lower modulation signal, and after introducing a first delay and a second delay respectively, convert them into a first electrical signal and a second electrical signal; and a frequency measurement module, configured to calculate a power comparison value between the first electrical signal and the second electrical signal, and to obtain the frequency of the microwave signal to be measured based on a preset mapping relationship between the power comparison value and the microwave signal frequency.

[0006] Optionally, the system further includes a power comparison function training module for constructing a power comparison function. The power comparison function training module includes: an acquisition module for acquiring multiple sets of training data of the first electrical signal and the second electrical signal, and for each set of training data, calculating the power comparison value between each pair of training data to obtain multiple microwave signal frequencies and the corresponding power comparison values; wherein the training data is obtained by inputting multiple microwave signals of known frequencies into an amplitude measurement module; and a function optimization module for fitting the obtained power comparison function using a machine learning algorithm based on the multiple microwave signal frequencies and the corresponding power comparison values.

[0007] Optionally, the amplitude measurement module includes: a light source module for providing a continuous broadband optical signal; a microwave signal modulation module for modulating the microwave signal under test onto the broadband optical signal to generate a modulation signal; a delay introduction module for dividing the modulation signal into an upper modulation signal and a lower modulation signal, and introducing different delays for each; and a photoelectric conversion module for converting the upper modulation signal and the lower modulation signal into the first electrical signal and the second electrical signal.

[0008] Optionally, the delay introduction module includes: a second polarization controller for adjusting the polarization state of the modulated signal to align with the main axis of the polarization multiplexing simulator; a polarization multiplexing simulator for introducing the modulated signal into the first delay; an optical coupler for splitting the modulated signal into an upper-path modulated signal and a lower-path modulated signal; a first polarizer for polarization combining the polarization state of the upper-path modulated signal; a third polarization controller for adjusting the polarization state of the lower-path modulated signal to align with the main axis of the polarization-maintaining fiber; and a polarization-maintaining fiber for introducing the lower-path modulated signal into the second delay; A dual polarizer is used to combine the polarization states of the lower modulation signal; a first optical circulator is used to inject the upper modulation signal into the dispersive element, and simultaneously inject the lower modulation signal output by the dispersive element into the first photodetector unit; the dispersive element is used to introduce delays into the different frequency components of the upper and lower modulation signals, thereby constructing a continuous-time impulse response; a second optical circulator is used to inject the lower modulation signal into the dispersive element, and simultaneously inject the upper modulation signal output by the dispersive element into the second photodetector unit.

[0009] Optionally, the polarization multiplexing simulator includes a second polarization beamsplitter, a mirror group, and a second polarization beam combiner; wherein the first delay is adjusted by adjusting the position of the mirror group.

[0010] Optionally, the microwave signal modulation module under test includes: a first polarization controller, used to adjust the polarization state of the broadband optical signal to be at a 45° angle to the input principal axis of the polarization-multiplexed dual-drive Mach-Zehnder modulator; and a polarization-multiplexed dual-drive Mach-Zehnder modulator, used to modulate the microwave signal under test onto the broadband optical signal to generate a modulation signal; wherein the polarization-multiplexed dual-drive Mach-Zehnder modulator includes: a first polarization beam splitter, a first dual-drive Mach-Zehnder modulator, a second dual-drive Mach-Zehnder modulator, and a first polarization beam combiner; the microwave signal under test is input into the first dual-drive Mach-Zehnder modulator and modulated onto the broadband optical signal to generate the modulation signal.

[0011] Optionally, the light source module includes: a broadband light source for generating a continuous broadband light wave signal; and a spectral shaping device for performing spectral shaping on the broadband light wave signal.

[0012] Optionally, the photoelectric conversion module includes: a first photoelectric detection unit for converting the upper-path modulation signal into the first electrical signal; and a second photoelectric detection unit for converting the lower-path modulation signal into the second electrical signal.

[0013] On the other hand, this disclosure provides a microwave frequency measurement method, comprising: modulating a microwave signal to be measured onto a continuous broadband optical signal to generate a modulation signal; dividing the modulation signal into an upper modulation signal and a lower modulation signal, and after introducing different delays, converting them into a first electrical signal and a second electrical signal; calculating the power comparison value between the first electrical signal and the second electrical signal; and obtaining the frequency of the microwave signal to be measured based on a preset mapping relationship between the power comparison value and the microwave signal frequency.

[0014] Optionally, the microwave frequency measurement method further includes constructing a power comparison function. Constructing the power comparison function includes: acquiring multiple sets of training data for the first electrical signal and the second electrical signal; for each set of training data, calculating the power comparison value between each pair of training data to obtain multiple microwave signal frequencies and the corresponding power comparison values; wherein the training data is obtained by inputting multiple microwave signals of known frequencies into the amplitude measurement module; and based on the multiple microwave signal frequencies and the corresponding power comparison values, fitting the obtained power comparison function using a machine learning algorithm.

[0015] As can be seen from the above technical solutions, the microwave frequency measurement system and method based on machine learning proposed in this invention have the following beneficial effects:

[0016] (1) By constructing a power comparison value, parameters that are difficult to measure in the microwave signal under test can be eliminated, and common-mode noise can be eliminated.

[0017] (2) By using machine learning algorithms to optimize multiple power comparison functions, the optimal mapping relationship between frequency and power comparison values ​​is obtained, and the error caused by differential mode noise is eliminated. This makes the frequency measurement results more accurate.

[0018] (3) This disclosure can achieve flexible reconstruction of power comparison values ​​by simply adjusting the polarization multiplexer, which can broaden the frequency measurement range of the microwave frequency measurement system and improve reconfigurability.

[0019] By utilizing a broadband light source and dispersive elements, the microwave signal under test is loaded onto a multi-frequency light source, and different delays are introduced for different frequencies, thereby forming a continuous-time impulse response and improving measurement accuracy. Attached Figure Description

[0020] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0021] Figure 1 A microwave frequency measurement system according to an embodiment of the present disclosure is illustrated schematically.

[0022] Figure 2 The schematic diagram illustrates a specific assembly structure of a microwave frequency measurement system according to an embodiment of the present disclosure.

[0023] Figure 3 A schematic diagram of the structure of a polarization multiplexed dual-drive Mach-Zehnder modulator 520 according to an embodiment of the present disclosure is shown.

[0024] Figure 4 A schematic diagram of the structure of a polarization multiplexing simulator 620 according to an embodiment of the present disclosure is shown.

[0025] Figure 5 A schematic diagram of a power comparison function training module of a microwave frequency measurement system according to an embodiment of the present disclosure is shown.

[0026] Figure 6 A schematic diagram of a microwave frequency measurement method according to an embodiment of the present disclosure is shown.

[0027] Figure 7A The diagram illustrates the spectrum of an optical signal before it enters the modulator according to an embodiment of the present disclosure.

[0028] Figure 7B The diagram illustrates the spectrum of an optical signal modulated by a modulator according to an embodiment of the present disclosure.

[0029] Figure 8A The diagram illustrates the spectrum of the optical signal after it has passed through a polarization multiplexing simulator according to an embodiment of the present disclosure.

[0030] Figure 8B The diagram illustrates the spectrum of an optical signal passing through a polarization multiplexing simulator and a polarization-maintaining fiber according to an embodiment of the present disclosure.

[0031] Figure 9A A schematic diagram of the spectrum of the frequency transfer function constructed by the uplink optical signal according to an embodiment of the present disclosure is shown.

[0032] Figure 9B A schematic diagram of the spectrum of the frequency transfer function constructed by the downlink optical signal according to an embodiment of the present disclosure is shown.

[0033] Figure 10A The diagram illustrates the spectrum of the power comparison function before optimization by a machine learning algorithm according to an embodiment of the present disclosure.

[0034] Figure 10B The diagram illustrates the spectrum of the power comparison function after optimization by a machine learning algorithm according to an embodiment of the present disclosure.

[0035] Figure 11A The diagram illustrates test results before optimization of the machine learning algorithm according to an embodiment of the present disclosure.

[0036] Figure 11B The image shows the test results after optimizing the machine learning algorithm for a specific embodiment of the present invention. Detailed Implementation

[0037] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0038] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0039] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0040] Figure 1 This illustration schematically depicts a microwave frequency measurement system provided in an embodiment of the present disclosure. The system includes an amplitude measurement module 100 and a frequency measurement module 200. See also... Figure 1 , combined Figures 2-5 The microwave frequency measurement system provided in this disclosure will be described in detail.

[0041] The amplitude measurement module 100 is used to modulate the microwave signal to be measured onto a continuous broadband optical signal to generate a modulation signal, and to divide the modulation signal into an upper modulation signal and a lower modulation signal, and after introducing a first delay and a second delay respectively, convert them into a first electrical signal and a second electrical signal.

[0042] The amplitude measurement module 100 also includes: a light source module 400, a microwave signal modulation module 500, a delay introduction module 600, and a photoelectric conversion module 700. Figure 2 The diagram schematically illustrates the specific device structure of each module in the amplitude measurement module 100 of this embodiment.

[0043] In this embodiment of the disclosure, the light source module 400 of the amplitude measurement module 100 is used to provide a continuous broadband optical signal. The light source module 400 includes 410 and a spectral shaping device 420.

[0044] The broadband light source 410 is used to generate continuous broadband light wave signals.

[0045] The spectral shaping device 420 is used to perform spectral shaping on the optical signal. It performs a Fourier transform on the light wave from the broadband light source.

[0046] The microwave signal modulation module 500 provided in the embodiments of this disclosure is used to modulate the microwave signal under test onto the optical wave signal to generate a modulated signal. The microwave signal modulation module 500 includes a first polarization controller 510 and a polarization multiplexing dual-drive Mach-Zehnder modulator 520.

[0047] In this embodiment, the first polarization controller 510 is used to adjust the polarization state of the broadband optical signal generated by the broadband light source, so that it forms a 45° angle with the principal axis of the polarization combiner 521 in the polarization multiplexing dual-drive Mach-Zehnder modulator 520, ensuring that the power of the broadband optical signal entering the two dual-drive Mach-Zehnder modulators is equal. A schematic diagram of the optical signal spectrum output by the first polarization controller 521 is shown below. Figure 7A As shown.

[0048] The polarization multiplexing dual-drive Mach-Zehnder modulator 520 is used to modulate the microwave signal under test onto the broadband optical signal to generate a modulated signal.

[0049] In the embodiments of this disclosure, a schematic diagram of the polarization multiplexing dual-drive Mach-Zehnder modulator 520 is shown below. Figure 3 As shown, the modulator consists of a first polarization beamsplitter 521, a first dual-drive Mach-Zehnder modulator 522, a second dual-drive Mach-Zehnder modulator 523, and a first polarization beam combiner 524. The first polarization beamsplitter splits the shaped broadband optical signal into two broadband optical signals of equal power. The modulator includes a first dual-drive Mach-Zehnder modulator 522 and a second dual-drive Mach-Zehnder modulator 523, which are respectively placed on upper and lower arms. A phase modulator 525 is placed on the upper and lower arms of each dual-drive Mach-Zehnder modulator. The first polarization beam combiner 524 combines the two polarized beams output from the first dual-drive Mach-Zehnder modulator 522 and the second dual-drive Mach-Zehnder modulator 523.

[0050] The microwave signal to be measured is split into two signals of equal energy, which are respectively input into the two phase modulators 525 of the first dual-drive Mach-Zehnder modulator 522 and modulated onto a broadband optical signal. The second dual-drive Mach-Zehnder modulator 523 does not receive the microwave signal to be measured.

[0051] The spectrum diagram of the output modulated signal of the polarization multiplexed dual-drive Mach-Zehnder modulator 520 is shown below. Figure 7B As shown, the modulated signals in the two polarization states can be represented as follows:

[0052] ;

[0053] ;

[0054] Wherein, N(Ω) k ) represents the k-th effective frequency component in the spectrum of a broadband light source, Ω. k Let ω be the angular frequency of the kth effective frequency component, the amplitude and angular frequency of the incident light signal. uf Let β be the angular frequency of the microwave signal to be measured, J0 be the zeroth-order Bessel function, and J1 be the first-order Bessel function. u =πV u / V π The modulation coefficient of the microwave signal under test is denoted as . It is the signal modulated by the first dual-drive Mach-Zehnder modulator 522. It is the signal modulated by the second dual-drive Machzed modulator 523.

[0055] The delay introduction module 600 provided in the embodiments of this disclosure is used to divide the modulation signal into the upper modulation signal and the lower modulation signal, and introduce different delays for each. The delay introduction module 600 includes: a second polarization controller 310, a polarization multiplexing simulator 620, an optical coupler 630, a first polarizer 640, a third polarization controller 650, a polarization-maintaining fiber 660, a second polarizer 670, a first optical circulator 680, a dispersive element 690, and a second optical circulator 685.

[0056] The modulation signal passes through the second polarization controller 610, aligning the orthogonal polarization modulation signal with the main axis of the polarization multiplexing simulator 620d. A schematic diagram of the polarization multiplexing simulator 620 is shown below. Figure 4 As shown, it includes a second polarization beam splitter 621, a lens group 622, and a second polarization beam combiner 623. The lens group 622 consists of a first lens 624, a second lens 625, and a third lens 626.

[0057] The modulation signal is subjected to a first delay Δτ1 by a polarization multiplexing simulator on the modulation signal in an orthogonal polarization state. A spectrum diagram is shown below. Figure 8A As shown, the output signal of the polarization multiplexing simulator is:

[0058] ;

[0059] In this embodiment of the present disclosure, the first delay can be adjusted by adjusting the position of each lens in the lens group 322 of the polarization multiplexing simulator 620.

[0060] In this embodiment of the disclosure, the optical coupler 630 may be a T-type optical coupler, which divides the modulation signal after the introduction of the first delay Δτ1 into an upper modulation signal and a lower modulation signal.

[0061] The spectrum diagram of the modulated signal is as follows: Figure 8B As shown, the modulated signal passes through the first polarizer 640, the first optical circulator 680 first channel, the dispersive element 690, and the second optical circulator 685.

[0062] After the lower-path modulation signal is adjusted by the third polarization controller 650, the polarization state of the lower-path modulation signal is aligned with the main axis of the polarization-maintaining fiber. After passing through the polarization-maintaining fiber 660, an unchangeable second delay Δτ2 is introduced. The spectrum diagram is shown below. Figure 8B As shown. After the lower-path modulation signal is introduced with a second delay Δτ2, it is combined by the second polarizer 670, and then passes through the second optical circulator 685, the dispersive element 690, and the first optical circulator 680.

[0063] In this embodiment, the polarization-maintaining fiber 660 is used to introduce a second delay Δτ2 into the lower modulation signal, making the delays of the upper and lower modulation signals different.

[0064] In this embodiment, the first polarizer 640 and the second polarizer 670 are used to combine the positively polarized states of the upper and lower modulation signals in both vertical and parallel directions. The first optical circulator 680 and the second optical circulator 685 in the delay module 600 of this embodiment are multi-port isolation devices that can change the direction of light without loss of output. For example, the first optical circulator 680 and the second optical circulator 685 can be four-port circulators. The upper modulation signal is input from port 1 of the first optical circulator, output from port 2, passes through the dispersive element 690, input to port 1 of the second optical circulator, and output from port 2. The lower modulation signal is input from port 3 of the second optical circulator, output from port 4, passes through the dispersive element 690, input to port 3 of the first optical circulator, and output from port 4. The upper and lower modulation signals do not affect each other when propagating in the first optical circulator 680 and the second optical circulator 685.

[0065] In this embodiment of the disclosure, the dispersive element 690 introduces different frequency components of the upper and lower modulation signals into a relative delay, thereby forming a continuous-time impulse response.

[0066] In this embodiment, the delay module 600 constructs two optical links with different delays, and the introduced delay can be adjusted using the polarization multiplexing simulator 620. Using two optical circulators allows the system to introduce different delays for different frequencies of the two modulated signals using only one dispersive element, reducing system cost.

[0067] In this embodiment, a photoelectric conversion module 700 is used to perform photoelectric conversion on the upper and lower modulation signals. The photoelectric conversion module 700 includes a first photoelectric detection unit 710 and a second photoelectric detection unit 720.

[0068] The modulated signal passes through the first polarizer 640, the first channel of the first optical circulator 680, the dispersive element 690, and the second optical circulator 685, and is detected by the first photoelectric detection unit 720, converting it into a first electrical signal. The spectrum diagram of the first electrical signal is shown below. Figure 9A As shown, the amplitude response is expressed as:

[0069] ;

[0070] Among them, H b (ω) represents the baseband response of the microwave frequency measurement system, and it has a Fourier transform relationship with the shape of the broadband light source obtained after shaping. ω is the frequency of the microwave signal under test. Adjusting the polarization multiplexing simulator 620 will cause a frequency shift in the response, and the magnitude of the frequency shift is proportional to the first delay of the upper-channel modulation signal.

[0071] The down-path modulated signal, after being adjusted by the third polarization controller 650, passes through the polarization-maintaining fiber 660, is introduced into the second delay Δτ2, and then passes through the second polarizer 670, the second optical circulator 685, the dispersive element 690, and the first optical circulator 680. Finally, it is detected by the second photoelectric detection unit 720 and converted into a second electrical signal. The spectrum diagram of the second electrical signal is shown below. Figure 9B As shown, the amplitude response is expressed as:

[0072] ;

[0073] When the polarization multiplexing simulator 620 is adjusted, the response will undergo a frequency shift, and the magnitude of the frequency shift is proportional to the first delay Δτ1 of the lower modulation signal.

[0074] The function construction module 510 obtains the power comparison value by dividing the first electrical signal detected by the first detector 410 and the second detector 420 by the second electrical signal. The spectrum diagram is shown below. Figure 10A As shown, it is represented as:

[0075] ;

[0076] in, Let be the dispersion coefficient of the dispersive element. Since the dispersion coefficient... The second delay Δτ2 and the frequency of the microwave signal under test Since neither of these parameters can be changed, the first delay Δτ1 is the only adjustable parameter in the above formula. Different frequency measurement ranges can be obtained by adjusting the first delay Δτ1. For example, when the first delay Δτ1 is 12.5 ps, a frequency measurement range of 4 to 6 GHz can be achieved, and when the first delay Δτ1 is 25 ps, a frequency measurement range of 8 to 10 GHz can be achieved.

[0077] The frequency of the microwave signal under test is obtained based on the preset mapping relationship between the power comparison value and the microwave signal frequency.

[0078] The microwave measurement system provided in this disclosure can eliminate difficult-to-measure parameters and suppress common-mode noise by constructing power comparison values. The range of measurement frequencies of the microwave frequency measurement system can be changed by altering the first delay Δτ1, thus achieving system reconfigurability.

[0079] The microwave measurement system provided in this disclosure also includes a power comparison function training module 300, used to construct the mapping relationship between power comparison values ​​and frequency, i.e., the power comparison function. Figure 5 As shown, the power comparison function training module 300 includes an acquisition module 310 and a function optimization module 320.

[0080] The acquisition module 310 is used to acquire multiple sets of training data of the first electrical signal and the second electrical signal, and for each set of training data, calculate the power comparison value between each pair of training data to obtain multiple sets of microwave signal frequencies and the corresponding power comparison values.

[0081] The training data mentioned above were obtained by inputting multiple microwave signals of known frequencies into the amplitude measurement module 100. Multiple power comparison values ​​were obtained by dividing each pair of the first and second electrical signals. By changing the first delay Δτ1 during multiple measurements, more accurate power comparison values ​​were achieved for measuring different frequency ranges.

[0082] By constructing a power comparison function, parameters that are difficult to measure in microwave signals can be eliminated, as well as common-mode noise. Furthermore, there is a unique mapping relationship between the power comparison value and the microwave signal frequency. However, the detected amplitude signal still suffers from differential-mode noise during transmission due to optical path jitter, such as… Figure 11A As shown.

[0083] The function optimization module 320 of the power comparison function training module 300 in this embodiment of the present disclosure is used to obtain a power comparison function by fitting discrete data based on multiple sets of microwave signal frequencies and corresponding power comparison function values ​​obtained by the power comparison function training module 310, using a machine learning algorithm. The machine algorithm may include various machine learning algorithms, including but not limited to K-nearest neighbors, support vector machines, multinomial regression, random forests, and ensemble learning algorithms. A schematic diagram of the spectrum of the optimized power comparison function is shown below. Figure 10B As shown, the measurement results are as follows Figure 11B As shown.

[0084] By using machine learning algorithms to fit a power comparison function, the error caused by differential-mode noise can be optimized, resulting in a more accurate mapping relationship between microwave frequency and power comparison value. Using this optimized mapping relationship to measure microwave signals of unknown frequencies can improve measurement accuracy.

[0085] This disclosure also provides a microwave frequency measurement method, such as... Figure 6 As shown, this includes operations S201 to S204.

[0086] Operation S210 modulates the microwave signal to be tested onto a continuous broadband optical signal to generate a modulation signal. The modulation signal is divided into an upper modulation signal and a lower modulation signal, and after introducing different delays, they are converted into a first electrical signal and a second electrical signal.

[0087] Operation S210 calculates the power comparison value between the first electrical signal and the second electrical signal, and obtains the frequency of the microwave signal to be tested based on the preset mapping relationship between the power comparison value and the microwave signal frequency.

[0088] The microwave frequency measurement method provided in this embodiment further includes constructing a power comparison function, comprising: acquiring multiple sets of training data for the first electrical signal and the second electrical signal; calculating power comparison values ​​between each pair of training data for each set of training data to obtain multiple microwave signal frequencies and corresponding power comparison values. The training data is obtained by inputting multiple microwave signals of known frequencies into the amplitude measurement module 100. Based on the multiple microwave signal frequencies and their corresponding power comparison values, a machine learning algorithm is used to fit the obtained power comparison function.

[0089] It should be noted that the methods in the embodiments of this disclosure are applied to the systems in the embodiments of this disclosure, and the beneficial effects of the microwave frequency measurement method are described in the section on microwave frequency measurement systems, and will not be repeated here.

[0090] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0091] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A microwave frequency measurement system, characterized in that, include: An amplitude measurement module is used to modulate the microwave signal to be measured onto a continuous broadband optical signal to generate a modulated signal, and to divide the modulated signal into an upper modulated signal and a lower modulated signal, and after introducing a first delay and a second delay respectively, convert them into a first electrical signal and a second electrical signal. The frequency measurement module is used to calculate the power comparison value between the first electrical signal and the second electrical signal, and obtain the frequency of the microwave signal under test based on a preset power comparison function. The amplitude measurement module includes: The light source module is used to provide continuous broadband optical signals; A microwave signal modulation module is used to modulate the microwave signal under test onto the broadband optical signal to generate a modulation signal. A delay introduction module is used to divide the modulation signal into the upper modulation signal and the lower modulation signal, and introduce different delays for each; A photoelectric conversion module is used to convert the upper-path modulation signal and the lower-path modulation signal into the first electrical signal and the second electrical signal; The delay introduction module includes: The second polarization controller is used to adjust the polarization state of the modulated signal and align it with the main axis of the polarization multiplexing simulator; A polarization multiplexing simulator is used to introduce the modulation signal into the first delay; An optical coupler is used to divide the modulation signal into an upper modulation signal and a lower modulation signal; The first polarizer is used to combine the polarization states of the upper-path modulated signal. The third polarization controller is used to adjust the polarization state of the down-path modulation signal and align it with the polarization-maintaining fiber spindle. Polarization-maintaining fiber is used to introduce the downstream modulation signal into the second delay; The second polarizer is used to combine the polarization states of the lower-path modulation signal. The first optical circulator is used to inject the upper modulation signal into the dispersive element, and at the same time inject the lower modulation signal output by the dispersive element into the first photoelectric detection unit. Dispersive elements are used to introduce delays into different frequency components of the upper-path modulation signal and the lower-path modulation signal, thereby constructing a continuous-time impulse response; The second optical circulator is used to inject the lower modulation signal into the dispersive element, and at the same time inject the upper modulation signal output by the dispersive element into the second photodetector unit. The polarization multiplexing simulator includes a second polarization beam splitter, a mirror group, and a second polarization beam combiner; wherein the first delay is adjusted by adjusting the position of the mirror group.

2. The microwave frequency measurement system according to claim 1, characterized in that, The system further includes a power comparison function training module for constructing a power comparison function, the power comparison function training module comprising: The acquisition module is used to acquire multiple sets of training data of the first electrical signal and the second electrical signal, and for each set of training data, calculate the power comparison value between each pair of training data to obtain multiple microwave signal frequencies and the corresponding power comparison value. The training data is obtained by inputting microwave signals of multiple known frequencies into the amplitude measurement module; The function optimization module is used to fit a power comparison function obtained by using a machine learning algorithm based on multiple microwave signal frequencies and the corresponding power comparison values.

3. The microwave frequency measurement system according to claim 1, characterized in that, The microwave signal modulation module under test includes: The first polarization controller is used to adjust the polarization state of the broadband optical signal to be at a 45° angle to the input main axis of the polarization multiplexing dual-drive Mach-Zehnder modulator; A polarization-multiplexed dual-drive Mach-Zehnder modulator is used to modulate the microwave signal under test onto the broadband optical signal to generate a modulated signal. The polarization multiplexing dual-drive Mach-Zehnder modulator includes: a first polarization beam splitter, a first dual-drive Mach-Zehnder modulator, a second dual-drive Mach-Zehnder modulator, and a first polarization beam combiner. The microwave signal to be tested is input into the first dual-drive Mach-Zehnder modulator and modulated onto the broadband optical signal to generate the modulated signal.

4. The microwave frequency measurement system according to claim 1, characterized in that, The light source module includes: Broadband light source, used to generate continuous broadband light wave signals; A spectral shaping device is used to perform spectral shaping on the broadband optical signal.

5. The microwave frequency measurement system according to claim 1, characterized in that, The photoelectric conversion module includes: The first photoelectric detection unit is used to convert the upper-path modulation signal into the first electrical signal; The second photoelectric detection unit is used to convert the lower-path modulation signal into the second electrical signal.

6. A microwave frequency measurement method, applied to the system described in any one of claims 1 to 5, characterized in that, include: The microwave signal to be tested is modulated onto a continuous broadband optical signal to generate a modulated signal. The modulated signal is divided into an upper modulated signal and a lower modulated signal, and after introducing different delays, it is converted into a first electrical signal and a second electrical signal. Calculate the power comparison value between the first electrical signal and the second electrical signal, and obtain the frequency of the microwave signal to be tested based on the preset mapping relationship between the power comparison value and the microwave signal frequency.

7. The microwave frequency measurement method according to claim 6, characterized in that, The method further includes constructing a power comparison function, which includes: Multiple sets of training data for the first electrical signal and the second electrical signal are acquired. For each set of training data, the power comparison value between each pair of training data is calculated to obtain multiple microwave signal frequencies and the corresponding power comparison values. The training data is obtained by inputting microwave signals of multiple known frequencies into the amplitude measurement module; A power comparison function is obtained by fitting multiple microwave signal frequencies and their corresponding power comparison values ​​using a machine learning algorithm.

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