Instantaneous frequency measurement device and method based on light intensity coding
Through the optical intensity encoding technology, the delay interference encoding of optical frequency combs and multiple optical channels is used to solve the problem of large equipment and low accuracy of the microwave frequency measurement system in ultra-wideband signal processing, and low power consumption and high Accurate microwave signal frequency measurement, suitable for fast response needs in complex electromagnetic environments.
Patent Information
- Application Number
- CN202411343934.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2024-12-31
AI Technical Summary
The existing microwave frequency measurement systems have problems such as large equipment, large volume, high power consumption and high cost in ultra-wideband signal processing, and the existing instantaneous frequency measurement methods are difficult to achieve high accuracy and rapid response.
Using an instantaneous frequency measurement device based on light intensity encoding, the optical filter, optical attenuator, through optical frequency comb, modulator, optical wave decomposition multiplexer, multiple optical channels, optical detector array and intensity encoding and demodulation module, the optical filter, optical attenuator, The optical beam splitter, optical delay and photosynthesis beam device realize multicast modulation of the measured radio frequency signal and delay interference encoding of the optical signal, and perform ultra-wideband signal frequency measurement.
It realizes ultra-wideband low-power, integrated rapid measurement of microwave signal frequency, reduces the performance requirements for detection equipment, has the ability to achieve high accuracy and fast response, and is suitable for signal processing in complex electromagnetic environments.
Smart Images
Figure CN119232254A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of microwave photons and relates to an instantaneous frequency measurement device and method based on light intensity coding. Background Art
[0002] With the continuous development of radar and other fields, the ability to transmit, receive and process ultra-wideband radio frequency signals has been continuously improved, and its working bandwidth has been continuously expanded. The microwave frequency measurement system based on traditional microwave devices has been severely limited in terms of working bandwidth. At the same time, the microwave frequency measurement system has the problems of large equipment quantity, volume and power consumption, and high cost. However, microwave photon technology has obvious advantages over microwave devices in terms of volume, weight and energy consumption, because it is not affected by electromagnetic interference, especially its excellent signal processing capability in ultra-wideband, which has also attracted wide attention and application in the field of frequency measurement. For example, the invention patent with application publication number CN113391136A discloses a microwave photon frequency measurement device and method based on fixed low-frequency detection, which adopts a frequency shifter that suppresses the carrier double-sideband modulation signal to pass through a dispersive medium and a small frequency shift amount respectively, and detects the heterodyne beat frequency of the dispersed light signal and the frequency-shifted light signal. It only needs to detect the fixed low-frequency frequency component signal to realize the measurement of the power attenuation transfer function generated by the high-frequency microwave signal frequency passing through the dispersive medium.
[0003] Instantaneous frequency measurement is to measure the spectrum of the received microwave signal with a large frequency range, high accuracy and fast speed. At present, there are three main methods for instantaneous frequency measurement based on microwave photonics: channel method, scanning method and power mapping method. The basic principles and application scenarios of these three methods are different: (1) The frequency measurement accuracy of the channel method frequency measurement scheme is relatively poor and requires spectroscopic processing. As the number of channels increases, the power dynamic range of the detection signal will decrease. In contrast, the channel method has the advantages of a large frequency measurement range and real-time measurement, and can be used in certain specific requirements that do not require high frequency measurement accuracy. (2) Compared with the channel method, the scanning method has higher frequency measurement accuracy, which can reach the megahertz level. However, since the tunable optical filter used for scanning in the scanning method often adopts mechanical, thermal and optical tuning methods, the system response time is relatively long. During the frequency scanning process, the pulse signal may be missed, which is not conducive to the spectrum monitoring of the received signal containing a short-duration pulse signal. (3) Compared with the channel method and the scanning method, the power mapping method does not require any other high-frequency devices except the electro-optical modulator to achieve the frequency measurement of microwave signals, and the error of frequency measurement is in the order of hundreds of megahertz. The measurement range is generally within 20 GHz. However, due to the nonlinearity of the power mapping function, the measurement accuracy within its frequency measurement range is not the same.
[0004] Based on the above, it can be seen that the existing instantaneous frequency measurement method meets the high-precision and fast measurement requirements of broadband receivers for microwave signal spectra in a large frequency range under the existing complex electromagnetic environment. Therefore, it is particularly important to propose a microwave signal frequency measurement device that can simultaneously achieve ultra-wideband fast response and high precision. Summary of the invention
[0005] The technical solution of the present invention is used to solve the problem that the frequency of ultra-wideband radio frequency signals measured in the prior art is difficult to meet the requirements of ultra-wideband fast response and high precision.
[0006] The present invention solves the above technical problems through the following technical solutions:
[0007] An instantaneous frequency measurement device based on light intensity coding comprises an optical frequency comb, a modulator, an optical wave demultiplexer, a multi-path optical channel, a light detector array and an intensity coding demodulation module connected in sequence;
[0008] The optical channel includes an optical filter, an optical attenuator, an optical beam splitter, an optical delay and an optical combiner connected in sequence; the input end of the optical filter is connected to the output end of the optical wavelength division multiplexer, the first output end of the optical beam splitter is connected to the first input end of the optical combiner through the optical delay to form a first optical path, the second output end of the optical beam splitter is connected to the second input end of the optical combiner to form a second optical path, and there is an optical delay difference between the first optical path and the second optical path; the output end of the optical combiner is connected to the input end of the optical detector array; the optical delay difference of the multiple optical channels is the same, and the optical phase difference increases in sequence.
[0009] Furthermore, the optical frequency comb outputs an optical comb signal, which includes a plurality of optical signals with different frequencies and uniform frequency distribution, and a frequency interval between adjacent optical signals is greater than twice the maximum frequency of the measured radio frequency signal.
[0010] Furthermore, the optical frequency comb outputs an optical comb signal as an optical carrier signal and is input into a modulator, the radio frequency signal under test is loaded into the radio frequency input terminal of the modulator, the optical frequency comb is multicast electro-optically modulated, and the radio frequency signal under test is simultaneously loaded onto multiple optical signals.
[0011] Furthermore, the modulator operates in a double-sideband modulation or carrier suppression modulation state.
[0012] Furthermore, the multiple output ends of the optical wavelength division multiplexer are respectively connected to multiple optical channels, the passband center frequencies of the optical channels correspond one-to-one to the frequencies contained in the optical comb signal, and the passband bandwidth is half of the frequency interval of adjacent optical signals; the modulated multiple optical signals are input into the optical channels of the corresponding frequency bands through the optical wavelength division multiplexer.
[0013] Furthermore, the optical attenuator is used to perform attenuation control on the optical signals of each optical channel to ensure that the optical powers of the optical signals of each optical channel are equal after passing through the optical attenuator.
[0014] Furthermore, the optical beam splitter divides the optical signal passing through the optical attenuator into two optical signals with completely equal power. The optical signals are respectively transmitted with delay through the first optical path and the second optical path, and then combined into one optical signal for output through the optical beam combiner.
[0015] Furthermore, the optical phase difference of each optical channel increases successively, and the delay difference of adjacent optical channels increases by a factor of 2; the optical signals output by multiple optical channels are detected by an optical detector array and the optical signals are encoded. If the optical detection power is higher than the average power, the optical channel is encoded as "1"; if the optical detection power is lower than the average power, the optical channel is encoded as "0"; each optical channel is encoded in sequence.
[0016] Furthermore, the DC signal output by the detector array is sent to the intensity coding demodulation module, and is interpreted according to the corresponding codes of each optical channel, so as to determine the wavelength position of the optical sideband, thereby obtaining the frequency of the measured radio frequency signal.
[0017] The present invention also provides an instantaneous frequency measurement method based on light intensity coding, comprising the following steps:
[0018] S100, the optical frequency comb outputs an optical comb signal, wherein the optical comb signal includes a plurality of optical signals with different frequencies and uniformly distributed frequencies, and the frequency interval between adjacent optical signals is greater than twice the maximum frequency of the measured radio frequency signal;
[0019] S200, the optical comb signal is input into the modulator as an optical carrier signal, the radio frequency signal under test is loaded into the radio frequency input terminal of the modulator, the optical frequency comb is multicast electro-optically modulated, and the radio frequency signal under test is loaded onto multiple optical signals at the same time;
[0020] S300, the modulated multiple optical signals are input into the optical channel of the corresponding frequency band through the optical wavelength division multiplexer, and the optical filter filters the optical signal input into the optical channel, and the optical signal after filtering can only pass a single optical sideband;
[0021] S400, optical attenuator controls the attenuation of the optical signal of each optical channel to ensure that the optical power of the optical signal of each optical channel is equal after passing through the optical attenuator
[0022] S500, the optical beam splitter splits the optical signal passing through the optical attenuator into two optical signals with completely equal power. The optical signals are respectively transmitted through the first optical path and the second optical path with delayed transmission, generating a fixed optical delay difference τ and an optical phase difference Φ1, and then are combined into one output optical power I1 through the optical combiner; the optical phase difference Φ1 generated by the wavelength of the upper sideband is specifically:
[0023] Φ1=2π(f0+f rf )τ
[0024] In the formula, f rf is the frequency of the RF signal to be measured, f0 is the frequency of the optical signal on the optical channel;
[0025] The output optical power I1 of the photosynthesizer is specifically:
[0026] I1=I+Icos(Φ1)=I+Icos[2π(f0+f rf )τ]
[0027] Wherein, I is the average power, which is the same as the power of the first optical path and the second optical path.
[0028] S600, the optical signals output by the multiple optical channels are detected by the optical detector array and the optical signals are encoded. k is an integer. If the optical detection power I1 is higher than the average power I, its optical channel is encoded as "1". Otherwise, if the optical detection power I1 is lower than the average power I, its optical channel is encoded as "0". Each optical channel is encoded in turn.
[0029] S700, the DC signal output by the optical detector array is sent to the intensity coding demodulation module, which is decoded according to the corresponding codes of each optical channel to determine the wavelength position of the optical sideband, thereby obtaining the frequency of the measured radio frequency signal.
[0030] The advantages of the present invention are: utilizing the advantages of ultra-wideband signal processing of microwave photon technology, modulating the measured radio frequency signal in the optical domain, utilizing optical frequency comb for multicast modulation, and encoding the light intensity DC signal of each channel through delayed interference of multiple optical channels, so as to realize ultra-wideband, low-power, integrated rapid measurement of microwave signal frequency in a light intensity coding manner, with lower requirements for signal acquisition and data processing. While giving full play to the advantages of microwave photon real-time processing and anti-electromagnetic interference, it does not require high-speed ultra-wideband radio frequency signal acquisition and processing, and significantly reduces the performance requirements for detection equipment. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 is a structural diagram of an instantaneous frequency measurement device based on light intensity coding according to an embodiment of the present invention;
[0032] Figure 2 It is a curve diagram showing the relationship between the amplitude-frequency response of each optical channel in the instantaneous frequency measurement device based on light intensity coding according to an embodiment of the present invention and the position relationship with the corresponding multicast optical signal. DETAILED DESCRIPTION
[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments 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.
[0034] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:
[0035] Embodiment 1
[0036] like Figure 1 As shown, specifically, an instantaneous frequency measurement device based on light intensity coding is disclosed, comprising an optical frequency comb, a modulator, an optical wavelength division multiplexer, a multi-path optical channel, a light detector array and an intensity coding demodulation module connected in sequence;
[0037] The optical channel includes an optical filter, an optical attenuator, an optical beam splitter, an optical delay and an optical combiner connected in sequence; the input end of the optical filter is connected to the output end of the optical wavelength division multiplexer, the first output end of the optical beam splitter is connected to the first input end of the optical combiner through the optical delay to form a first optical path, the second output end of the optical beam splitter is connected to the second input end of the optical combiner to form a second optical path, and there is an optical delay difference between the first optical path and the second optical path; the output end of the optical combiner is connected to the input end of the optical detector array; the optical delay difference of the multiple optical channels is the same, and the optical phase difference increases in sequence.
[0038] The optical frequency comb outputs an optical comb signal, which includes multiple optical signals with different frequencies and uniformly distributed frequencies, and the frequency interval between adjacent optical signals is greater than twice the maximum frequency of the measured radio frequency signal. The optical frequency comb can generate regularly spaced frequency lines (i.e., optical comb signals), and each optical comb tooth is actually a separate frequency signal. These frequency lines can cover a wide frequency range and are very precisely spaced. The optical frequency comb generates a series of precisely spaced frequency lines by emitting extremely short, repetitive light pulses. Each pulse contains a combination of a large number of different frequencies, forming a frequency comb for emitting a light beam containing widely and evenly distributed frequencies, showing the characteristics of a wide spectrum. The laser emitted by the optical frequency comb covers multiple different frequencies, and the different frequencies are strictly and evenly distributed, forming multiple sharp and evenly spaced spectral lines. By precisely controlling the phase and frequency of the laser, the coherence between different pulses can be maintained.
[0039] The optical frequency comb outputs an optical comb tooth signal as an optical carrier signal and is input into a modulator. The radio frequency signal to be measured is loaded into the radio frequency input terminal of the modulator. The optical frequency comb is subjected to multicast electro-optical modulation, and the radio frequency signal to be measured is simultaneously loaded onto multiple optical signals, so that the same information is transmitted simultaneously over multiple frequency bands.
[0040] The modulator can be operated in double-sideband modulation or carrier suppression modulation, and is used to generate corresponding modulation sidebands on both sides of each optical comb signal. Double-sideband modulation can make the spectrum of the optical signal generate symmetrical frequency bands on both sides of the carrier frequency through the interaction of the carrier signal and the modulation signal. The modulated optical signal contains the original optical comb signal frequency and two sideband frequencies. However, the spectrum of the optical signal after carrier suppression modulation does not contain the original optical comb signal frequency, but only contains two sideband frequencies, without the need for a central carrier component.
[0041] The multiple output ends of the optical wavelength division multiplexer are respectively connected to multiple optical channels, and the passband center frequency of each optical channel corresponds to each frequency contained in the optical comb signal, and the passband bandwidth is half of the frequency interval of adjacent optical signals. The modulated multiple optical signals are input into the optical channels of the corresponding frequency bands through the optical wavelength division multiplexer.
[0042] When the RF signal is modulated onto the optical comb signal, modulation sidebands will be generated on both sides of each optical signal frequency. If the passband bandwidth of the optical channel is equal to or greater than the interval between the optical comb teeth, the modulation sidebands of adjacent optical comb teeth may overlap into adjacent optical channels, resulting in signal interference and performance degradation. To ensure that each optical signal and the modulation sidebands it carries can be transmitted separately through their respective channels without being interfered by adjacent channels, the present invention limits the bandwidth of each optical channel so that each channel only transmits its corresponding optical comb teeth and their sidebands, accurately controlling the transmission of the signal, thereby improving the overall efficiency and signal quality of the system.
[0043] The optical filter filters the optical signal input to the optical channel, and the passband of the optical filter is larger than the frequency range of the measured radio frequency signal. Since the output values of the two sidebands will be different after interference, the superposition will affect the threshold judgment of the output optical power value in the later stage, and it is impossible to judge whether the frequency band of the signal falls within the corresponding frequency interval. Therefore, the optical signal after filtering by the optical filter can only pass a single optical sideband.
[0044] The optical filter may be an upper sideband filter or a lower sideband filter. In this embodiment, the upper sideband filter is selected as an example, and only the upper sideband passes through the optical signal after filtering.
[0045] The optical attenuator is used to perform attenuation control on the optical signals of each optical channel to ensure that the optical powers of the optical signals of each optical channel are equal after passing through the optical attenuator.
[0046] The optical beam splitter divides the optical signal passing through the optical attenuator into two optical signals with completely equal power. The optical signals are respectively transmitted with delay through the first optical path and the second optical path, and then combined into one output through the optical combiner. The first optical path and the second optical path form a Mach-Zehnder interference structure, but because the first optical path is connected to the optical combiner through an optical delay, there will be a fixed optical delay difference τ between the first optical path and the second optical path, so that there is a fixed optical phase difference Φ1 between the two signals. The size of the optical phase difference is related to the wavelength of the optical signal, and different wavelengths of optical sidebands correspond to different optical phase differences. This embodiment takes the first optical channel and the corresponding optical signal frequency on the optical channel as an example. Taking the upper sideband as an example, the optical phase difference Φ1 generated by the wavelength of the upper sideband is specifically:
[0047] Φ1=2π(f0+f rf )τ
[0048] In the formula, f rf is the frequency of the RF signal to be measured, and f0 is the frequency of the optical signal on the optical channel.
[0049] The optical powers output by the first optical path and the second optical path after interference and superposition by the optical combiner are also different. The optical power I1 output by the optical combiner is specifically:
[0050] I1=I+Icos(Φ1)=I+Icos[2π(f0+f rf )τ]
[0051] Wherein, I is the average power, which is the same as the power of the first optical path and the second optical path.
[0052] Since the optical delays of various optical channels are different, the optical phase differences of various optical channels in the present invention increase successively, and the delay difference between adjacent optical channels increases by a factor of 2. The larger the optical phase difference, the smaller the reflection fringe period of the interference output signal intensity in the corresponding optical channel, and the smaller the frequency interval length of the optical sideband that can be determined. Therefore, the optical channel with the largest optical phase difference determines the accuracy of the system frequency measurement.
[0053] The optical delay is a delay fiber or a delay waveguide, which is used to control the transmission time of the optical signal and adjust the propagation delay of the optical signal. When the optical delay adopts a delay fiber, the optical delay is achieved by increasing the length of the optical signal propagation path (i.e., the length of the delay fiber), and the delay amount of the optical delay is directly related to the length of the delay fiber; when the optical delay adopts a delay waveguide, the delay is achieved by designing a special optical waveguide path.
[0054] like Figure 2It is a graph of the amplitude-frequency response relationship of each optical channel in the instantaneous frequency measurement device and the position relationship with the corresponding multicast optical signal. The amplitude-frequency response curve of each optical channel presents periodicity, among which the optical phase difference of the first optical channel is the smallest, and the frequency interval of the optical comb signal is k times the period of the amplitude-frequency response curve of the first optical channel, k is a positive integer and k≥2, so as to ensure that the optical signal frequencies f1, f2, f3…f N The relative positions of the amplitude-frequency response curves corresponding to each optical channel are consistent.
[0055] The optical signals output by the multiple optical channels are detected by the optical detector array and the optical signals are encoded. If k is an integer, then if the optical detection power I1 is higher than the average power I, its optical channel is encoded as "1"; otherwise, if the optical detection power I1 is lower than the average power I, its optical channel is encoded as "0"; each optical channel is encoded in turn.
[0056] The photodetector array is formed by arranging multiple photodetectors in a matrix or array form, and can detect the output power of multiple optical channels at the same time. The bandwidth requirement of the photodetector is very low, and it only needs to detect the DC component. The DC signal output by the photodetector array is sent to the intensity coding demodulation module, and is interpreted according to the corresponding code of each optical channel. The code value of a single optical channel can determine the optical signal frequency f1, f2, f3...f through the code value from the first channel to the Nth channel. N There may be multiple ambiguity intervals, especially the Nth channel corresponding to the largest optical delay. The more ambiguity intervals there are, the more ambiguity intervals there are. However, the ambiguity can be removed by integrating the overlapping intervals of the N channels to determine the wavelength position of the optical sideband and thus obtain the frequency of the measured RF signal.
[0057] The present invention utilizes the advantages of ultra-wideband signal processing of microwave photon technology, modulates the measured radio frequency signal in the optical domain, uses an optical frequency comb for multicast modulation, and uses delayed interference of multiple optical channels to encode the light intensity DC signal of each channel. Ultra-wideband, low-power, integrated rapid measurement of microwave signal frequency is achieved in the form of light intensity coding, with lower requirements for signal acquisition and data processing. While giving full play to the advantages of microwave photon real-time processing and anti-electromagnetic interference, it does not require high-speed ultra-wideband radio frequency signal acquisition and processing, which significantly reduces the performance requirements for detection equipment.
[0058] The present invention also provides an instantaneous frequency measurement method based on light intensity coding, comprising the following steps:
[0059] S100, the optical frequency comb outputs an optical comb signal, wherein the optical comb signal includes a plurality of optical signals with different frequencies and uniformly distributed frequencies, and the frequency interval between adjacent optical signals is greater than twice the maximum frequency of the measured radio frequency signal;
[0060] S200, the optical comb signal is input into the modulator as an optical carrier signal, the radio frequency signal under test is loaded into the radio frequency input terminal of the modulator, the optical frequency comb is multicast electro-optically modulated, and the radio frequency signal under test is loaded onto multiple optical signals at the same time;
[0061] S300, the modulated multiple optical signals are input into the optical channel of the corresponding frequency band through the optical wavelength division multiplexer, and the optical filter filters the optical signal input into the optical channel, and the optical signal after filtering can only pass a single optical sideband;
[0062] S400, optical attenuator controls the attenuation of the optical signal of each optical channel to ensure that the optical power of the optical signal of each optical channel is equal after passing through the optical attenuator
[0063] S500, the optical beam splitter splits the optical signal passing through the optical attenuator into two optical signals with completely equal power. The optical signals are respectively transmitted through the first optical path and the second optical path with delayed transmission, generating a fixed optical delay difference τ and an optical phase difference Φ1, and then are combined into one output optical power I1 through the optical combiner; the optical phase difference Φ1 generated by the wavelength of the upper sideband is specifically:
[0064] Φ1=2π(f0+f rf )τ
[0065] In the formula, f rf is the frequency of the RF signal to be measured, f0 is the frequency of the optical signal on the optical channel;
[0066] The output optical power I1 of the photosynthesizer is specifically:
[0067] I1=I+Icos(Φ1)=I+Icos[2π(f0+f rf )τ]
[0068] Where I is the average power, which is the same as the power of the first light path and the second light path;
[0069] S600, the optical signals output by the multiple optical channels are detected by the optical detector array and the optical signals are encoded. k is an integer. If the optical detection power I1 is higher than the average power I, its optical channel is encoded as "1". Otherwise, if the optical detection power I1 is lower than the average power I, its optical channel is encoded as "0". Each optical channel is encoded in turn.
[0070] S700, the DC signal output by the optical detector array is sent to the intensity coding demodulation module, which is decoded according to the corresponding codes of each optical channel to determine the wavelength position of the optical sideband, thereby obtaining the frequency of the measured radio frequency signal.
[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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. An instantaneous frequency measurement device based on light intensity coding, characterized in that: It includes an optical frequency comb, a modulator, an optical wavelength division multiplexer, a multiple optical channel, an optical detector array and an intensity coding demodulation module connected in sequence; The optical channel comprises an optical filter, an optical attenuator, an optical beam splitter, an optical delay and an optical beam combiner connected in sequence; the input end of the optical filter is connected to the output end of the optical wavelength division multiplexer, the first output end of the optical beam splitter is connected to the first input end of the optical beam combiner through the optical delay to form a first optical path, the second output end of the optical beam splitter is connected to the second input end of the optical beam combiner to form a second optical path, and there is an optical delay difference between the first optical path and the second optical path; the output end of the optical beam combiner is connected to the input end of the photodetector array; The optical delay differences of the multiple optical channels are the same, and the optical phase differences increase in sequence.
2. The instantaneous frequency measurement device based on light intensity coding according to claim 1 is characterized in that: The optical frequency comb outputs an optical comb signal, which includes a plurality of optical signals with different frequencies and uniformly distributed frequencies, and a frequency interval between adjacent optical signals is greater than twice the maximum frequency of the radio frequency signal being measured.
3. The instantaneous frequency measurement device based on light intensity coding according to claim 2 is characterized in that: The optical frequency comb outputs an optical comb signal as an optical carrier signal and is input into a modulator. The radio frequency signal to be measured is loaded into the radio frequency input terminal of the modulator. The optical frequency comb is multicast electro-optically modulated and the radio frequency signal to be measured is simultaneously loaded onto multiple optical signals.
4. The instantaneous frequency measurement device based on light intensity coding according to claim 3 is characterized in that: The modulator working state is double sideband modulation or carrier suppression modulation.
5. The instantaneous frequency measurement device based on light intensity coding according to claim 1 is characterized in that: The multiple output ends of the optical wavelength division multiplexer are respectively connected to multiple optical channels, the passband center frequencies of the optical channels correspond one-to-one to the frequencies contained in the optical comb signal, and the passband bandwidth is half of the frequency interval of adjacent optical signals; the modulated multiple optical signals are input into the optical channels of the corresponding frequency bands through the optical wavelength division multiplexer.
6. The instantaneous frequency measurement device based on light intensity coding according to claim 5, characterized in that: The optical attenuator is used to perform attenuation control on the optical signals of each optical channel to ensure that the optical powers of the optical signals of each optical channel are equal after passing through the optical attenuator.
7. The instantaneous frequency measurement device based on light intensity coding according to claim 6 is characterized in that: The optical beam splitter divides the optical signal passing through the optical attenuator into two optical signals with completely equal power. The optical signals are respectively transmitted through the first optical path and the second optical path with delayed transmission, and then combined into one optical signal for output through the optical beam combiner.
8. The instantaneous frequency measurement device based on light intensity coding according to claim 7, characterized in that: The optical phase difference of each optical channel increases in sequence, and the delay difference of adjacent optical channels increases by a factor of 2. The optical signals output by multiple optical channels are detected by an optical detector array and the optical signals are encoded. If the optical detection power is higher than the average power, the optical channel is encoded as "1". If the optical detection power is lower than the average power, the optical channel is encoded as "0". Each optical channel is encoded in sequence.
9. The instantaneous frequency measurement device based on light intensity coding according to claim 8, characterized in that: The DC signal output by the detector array is sent to the intensity coding demodulation module, which is interpreted according to the corresponding codes of each optical channel to determine the wavelength position of the optical sideband, thereby obtaining the frequency of the measured radio frequency signal.
10. The instantaneous frequency measurement method based on light intensity coding according to any one of claims 1 to 9, characterized in that: The following steps are involved: S100, the optical frequency comb outputs an optical comb signal, wherein the optical comb signal includes a plurality of optical signals with different frequencies and uniformly distributed frequencies, and the frequency interval between adjacent optical signals is greater than twice the maximum frequency of the measured radio frequency signal; S200, the optical comb signal is input into the modulator as an optical carrier signal, the radio frequency signal under test is loaded into the radio frequency input terminal of the modulator, the optical frequency comb is multicast electro-optically modulated, and the radio frequency signal under test is loaded onto multiple optical signals at the same time; S300, the modulated multiple optical signals are input into the optical channel of the corresponding frequency band through the optical wavelength division multiplexer, and the optical filter filters the optical signal input into the optical channel, and the optical signal after filtering can only pass a single optical sideband; S400, optical attenuator controls the attenuation of the optical signal of each optical channel to ensure that the optical power of the optical signal of each optical channel is equal after passing through the optical attenuator S500, the optical beam splitter splits the optical signal passing through the optical attenuator into two optical signals with completely equal power. The optical signals are respectively transmitted through the first optical path and the second optical path with delayed transmission, generating a fixed optical delay difference τ and an optical phase difference Φ1, and then are combined into one output optical power I1 through the optical combiner; the optical phase difference Φ1 generated by the wavelength of the upper sideband is specifically: Φ1=2π(f0+f rf )t In the formula, f rf is the frequency of the RF signal to be measured, f0 is the frequency of the optical signal on the optical channel; The output optical power I1 of the photosynthesizer is specifically: I1=I+Icos(Φ1)=I+Icos[2π(f0+f rf )t] Where I is the average power, which is the same as the power of the first light path and the second light path; S600, the optical signals output by the multiple optical channels are detected by the optical detector array and the optical signals are encoded. k is an integer. If the optical detection power I1 is higher than the average power I, its optical channel is encoded as "1". Otherwise, if the optical detection power I1 is lower than the average power I, its optical channel is encoded as "0". Each optical channel is encoded in turn. S700, the DC signal output by the optical detector array is sent to the intensity coding demodulation module, which is decoded according to the corresponding codes of each optical channel to determine the wavelength position of the optical sideband, thereby obtaining the frequency of the measured radio frequency signal.