Signal measurement device and method, storage medium and computer program product
By using a combination of time domain stretching and dual-polarized dual-driven Mach Zengdel modulators in the signal measurement device, the problem of large errors in traditional microwave signal measurement methods is solved, and signal measurement with higher stability is achieved.
Patent Information
- Application Number
- CN202411691383.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-02-21
AI Technical Summary
Traditional microwave signal frequency and arrival angle measurement methods are susceptible to laser power fluctuations and pulse time jitters, resulting in measurement errors and reducing the stability of signal measurement.
Using the combination of pulse generation module, first dispersion module, signal modulation module, second dispersion module and signal detection module, the microwave signal is modulated through time domain stretching and dual-polarization dual-drive Mach Zengdel modulator to realize microwave signal accurate measurement of frequency and arrival angle.
By modulation, the RF power fading caused by dispersion is reduced, the microwave signal distortion is avoided, and the laser power fluctuation and pulse time jitter are avoided through time domain stretching, improving the stability and accuracy of signal measurement.
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Figure CN119496558A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of communication technology, and in particular to a signal measurement device, method, storage medium and computer program product. Background Art
[0002] The measurement of microwave signal frequency and angle of arrival (AOA) plays an important role in various fields such as satellite positioning, wireless communication, and electronic warfare. Due to the electronic bottleneck, the traditional electrical method of measuring frequency and AOA has great limitations.
[0003] Traditional technology uses a multi-parameter measurement method of two dispersive media, which essentially maps frequency domain information to the time domain, and derives the information of the microwave signal to be measured based on the time domain information between multiple pulses in a single cycle of the time domain. Since the frequency, amplitude, and arrival angle information of the final microwave signal in this scheme are calculated based on the time domain characteristics of the obtained electrical pulse, it will be affected by laser power fluctuations and pulse time jitter, which is prone to errors, thereby reducing the stability of signal measurement. Summary of the invention
[0004] The present application aims to solve at least one of the technical problems existing in the related art. To this end, the present application proposes a signal measurement device, method, storage medium and computer program product to solve the problem that traditional technology is prone to errors and improve the stability of signal measurement.
[0005] According to the first aspect of the present application, the signal measurement device comprises a pulse generation module, a first dispersion module, a signal modulation module, a second dispersion module and a signal detection module connected in sequence; the signal modulation module comprises a dual-polarization dual-drive Mach-Zehnder modulator; The first dispersion module is used to perform time domain stretching on the optical pulse generated by the pulse generation module; The signal modulation module is used to modulate the stretched optical pulse through the dual-polarization dual-drive Mach-Zehnder modulator based on the microwave signal received from the antenna; The second dispersion module is used to perform time domain stretching on the modulated optical pulses obtained by modulation; The signal detection module is used to perform signal detection on the stretched modulated light pulse to obtain the frequency and arrival angle of the microwave signal.
[0006] According to one embodiment of the present application, the signal measurement device further includes a phase shifter; the dual-polarization dual-drive Mach-Zehnder modulator includes two dual-drive Mach-Zehnder modulators; The phase shifter is used to phase shift one of the two signals of each microwave signal received from the antenna and then input the phase to the dual-polarization dual-drive Mach-Zehnder modulator; wherein different microwave signals are input to different dual-drive Mach-Zehnder modulators in the dual-polarization dual-drive Mach-Zehnder modulator after phase shift; The dual-drive Mach-Zehnder modulator is used to modulate the stretched optical pulse based on one signal after phase shift and the other signal without phase shift in two signals of the microwave signal.
[0007] According to one embodiment of the present application, the dual-polarization dual-drive Mach-Zehnder modulator further includes a polarization controller; The polarization controller is used to adjust the polarization state of the modulated light pulse output by any of the two dual-driven Mach-Zehnder modulators of the dual-polarization dual-driven Mach-Zehnder modulator.
[0008] According to one embodiment of the present application, the signal detection module includes a spectrum shaper, a polarization beam splitter, a photodetector, and a digital signal processing module; The spectrum shaper is used to perform spectrum shaping on the stretched modulated optical pulse to obtain a shaped optical signal; The polarization beam splitter is used to split the shaped optical signal into two paths and enter different photodetectors; The photoelectric detector is used to perform photoelectric conversion on the two optical signals to obtain low-frequency electrical signals; The digital signal processing module is used to analyze the two low-frequency electrical signals to obtain the frequency and arrival angle of the microwave signal.
[0009] According to the second aspect of the present application, the signal measurement method includes: Performing time-domain stretching on the generated light pulses; modulating the stretched optical pulses based on a microwave signal received from an antenna; Performing time domain stretching on the modulated optical pulse obtained by modulation; Signal detection is performed on the stretched modulated light pulse to obtain the frequency and arrival angle of the microwave signal.
[0010] According to one embodiment of the present application, the step of modulating the stretched optical pulse based on the microwave signal received from the antenna includes: For two microwave signals received from the antenna, phase shift is performed on one of the two signals of each microwave signal; For each microwave signal, the stretched optical pulse is modulated by the phase-shifted signal and the original signal.
[0011] According to an embodiment of the present application, after modulating the stretched optical pulse by the phase-shifted signal and the original signal for each microwave signal, the method further includes: adjusting the polarization state of any one of the two modulated optical pulses; The modulated optical pulse after polarization state adjustment is combined with another modulated optical pulse.
[0012] According to an embodiment of the present application, the step of performing signal detection on the stretched modulated optical pulse to obtain the frequency and arrival angle of the microwave signal includes: Performing spectrum shaping on the stretched modulated optical pulse to obtain a shaped optical signal; Splitting the shaped optical signal into two paths and respectively entering the photoelectric detector; Performing photoelectric conversion on the two optical signals respectively to obtain low-frequency electrical signals; The two low-frequency electrical signals are analyzed to obtain the frequency and arrival angle of the microwave signal.
[0013] According to the storage medium of the third aspect embodiment of the present application, the storage medium is a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements any of the signal measurement methods described above.
[0014] A computer program product according to an embodiment of the fourth aspect of the present application includes a computer program, which, when executed by a processor, implements any of the signal measurement methods described above.
[0015] The above one or more technical solutions in the embodiments of the present application have at least the following technical effects: After the optical pulse is generated by the pulse generation module, the optical pulse is stretched in the time domain by the first dispersion module; further, the stretched optical pulse is modulated by the signal modulation module based on the microwave signal received from the antenna, using the dual-polarization dual-drive Mach-Zehnder modulator therein; so that the modulated optical pulse obtained by modulation can be stretched in the time domain by the second dispersion module; and then the stretched modulated optical pulse is detected by the signal detection module to obtain the frequency and arrival angle of the microwave signal. By compensating for the RF power attenuation caused by dispersion through modulation, the distortion of the microwave signal can be reduced, and by avoiding the influence of laser power fluctuation and pulse time jitter through time domain stretching, errors can be avoided, thereby improving the stability of signal measurement.
[0016] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] 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.
[0018] Figure 1 Schematic diagram of the architecture of the signal measurement device provided in an embodiment of the present application.
[0019] Figure 2 This is a frequency domain diagram of the received signal after the DSP module provided in the embodiment of the present application removes the envelope.
[0020] Figure 3 It is a flow chart of the signal measurement method provided in the embodiment of the present application. DETAILED DESCRIPTION
[0021] The following is a further detailed description of the implementation of the present application in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but cannot be used to limit the scope of the present application.
[0022] In the description of the embodiments of the present application, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.
[0023] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.
[0024] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0025] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.
[0026] It should be noted that the traditional photon-assisted microwave signal multi-parameter measurement method uses the opposite dispersion coefficients of the two dispersive media before and after. In essence, it maps the frequency domain information to the time domain, and derives the information of the microwave signal to be measured based on the time domain information between multiple pulses in a single cycle of the time domain. Since the frequency, amplitude, and arrival angle information of the final microwave signal of this scheme are calculated through the time domain characteristics of the obtained electrical pulse, it will be affected by the laser power fluctuation and pulse time jitter, and it is easy to produce errors. If the measurement accuracy needs to be improved, the oscilloscope for signal capture has higher requirements.
[0027] Based on this, the present application proposes a signal measurement device, method, storage medium and computer program product.
[0028] The signal measurement device in the present application may sequentially connect a pulse generation module, a first dispersion module, a signal modulation module, a second dispersion module and a signal detection module.
[0029] The first dispersion module is used to perform time domain stretching on the optical pulse generated by the pulse generation module.
[0030] The signal modulation module is used to modulate the stretched optical pulse through a dual-polarization dual-drive Mach-Zehnder modulator based on the microwave signal received from the antenna.
[0031] The second dispersion module is used to perform time domain stretching on the modulated optical pulses obtained by modulation.
[0032] The signal detection module is used to perform signal detection on the stretched modulated light pulse to obtain the frequency and arrival angle of the microwave signal.
[0033] The pulse generating module is used as a pulse laser source, and specifically can be a mode-locked laser (Mode-Locked Laser, MLL).
[0034] The first dispersion module and the second dispersion module may be the same dispersion module. The dispersion module may be a device that provides dispersion such as a dispersion optical fiber or a chirped fiber Bragg grating, and the present application may be described using a single mode optical fiber (SMF) as an example.
[0035] The signal modulation module may include a dual-polarization dual-drive Mach-Zehnder modulator (DPol-DDMZM).
[0036] It should be noted that the signal measuring device also includes a phase shifter.
[0037] The dual-polarization dual-drive Mach-Zehnder modulator may include two dual-drive Mach-Zehnder modulators (DDMZM) and at least one polarization controller.
[0038] The phase shifter is used for phase shifting one of the two signals of each microwave signal received from the antenna and inputting the signal into the dual-polarization dual-drive Mach-Zehnder modulator; wherein different microwave signals are input into different dual-drive Mach-Zehnder modulators in the dual-polarization dual-drive Mach-Zehnder modulator after phase shifting.
[0039] Specifically, the phase shifter may be a 90-degree phase shifter.
[0040] A dual-drive Mach-Zehnder modulator is used to modulate the stretched optical pulse based on one signal after phase shift and the other signal without phase shift in two signals of the microwave signal.
[0041] The polarization controller is used for adjusting the polarization state of the modulated light pulse output by any of the two dual-driven Mach-Zehnder modulators of the dual-polarization dual-driven Mach-Zehnder modulator.
[0042] The polarization controller may specifically be a 90-degree polarization rotator (Polarization Rotator, PR).
[0043] The signal detection module may include a spectrum shaper (SS), a polarization beam splitter (PBS), a photodetector (PD), and a digital signal processing (DSP) module.
[0044] The spectrum shaper is used to perform spectrum shaping on the stretched modulated optical pulse to obtain a shaped optical signal.
[0045] Polarization beam splitter is used to split the shaped optical signal into two paths and enter different photodetectors.
[0046] The photoelectric detector is used to perform photoelectric conversion on the two optical signals to obtain low-frequency electrical signals.
[0047] The digital signal processing module is used to analyze two low-frequency electrical signals to obtain the frequency and arrival angle of the microwave signal.
[0048] Figure 1 is a schematic diagram of the architecture of a signal measurement device provided in an embodiment of the present application, such as Figure 1 As shown, in the present application, the pulsed laser source MLL generates optical pulses, which pass through the first section of dispersive optical fiber SMF for pulse broadening (specifically, time domain stretching) and then enter the optical input port of the dual-polarization dual-drive Mach-Zehnder modulator DPol-DDMZM respectively.
[0049] The electrical input port of the dual-polarization dual-drive Mach-Zehnder modulator inputs the microwave signals received by the two antennas (antenna 1 and antenna 2) respectively (the delay of the two microwave signals is set to , we can get , is the speed of light in vacuum, Usually set to , λ represents the wavelength of the microwave signal), one of the electrical signals of each dual-drive Mach-Zehnder modulator DDMZM passes through a 90-degree phase shifter, and single-sideband modulation is achieved by adjusting the bias voltage to work at the orthogonal bias point.
[0050] By using single-sideband modulation to compensate for the RF power attenuation caused by dispersion, time-domain stretching technology can reduce the difficulty of signal acquisition, so that all signals within the frequency band can be collected and analyzed. In this way, multi-frequency signals can be measured and the frequency resolution can be improved by reducing the pulse repetition frequency.
[0051] One of the two optical signals output from the dual-polarization dual-drive Mach-Zehnder modulator passes through a 90-degree polarization rotator PR and then is combined by the two signals, and then further stretched in the time domain through a second section of dispersive optical fiber SMF.
[0052] This application uses time domain stretching technology, which is usually used in large bandwidth frequency measurement. By controlling the dispersion ratio between the front and rear dispersion media, the stretching coefficient can be adjusted, greatly reducing the sampling difficulty and required sampling rate of the DSP module. The influence of laser optical power fluctuation and time jitter is avoided.
[0053] Furthermore, the spectrum is flattened by the spectrum shaper SS, and the optical signal output by the spectrum shaper is divided into two paths by the polarization beam splitter PBS and enters two photodetectors PD for photoelectric conversion to obtain low-frequency electrical signals, which are further analyzed and solved by the digital signal processing module DSP to obtain information such as the frequency and arrival angle of the microwave signal.
[0054] The present application utilizes the above-mentioned signal measurement device to simultaneously realize the functions of wide bandwidth frequency measurement and arrival angle measurement, suppresses microwave signal power attenuation introduced by dispersion through single-sideband modulation, has low requirements on the signal acquisition module, and realizes a simple and easy to integrate device.
[0055] More specifically, in the present application, after the light pulse emitted by the mode-locked laser enters the first section of dispersive optical fiber, it is stretched in the time domain through the dispersive optical fiber.
[0056] It should be noted that, assuming that the two sections of dispersive optical fiber in this application have the same dispersion coefficient, the transfer function and stretch coefficient of the two sections of dispersive optical fiber are As shown in the following formula: ; in, and Respectively represent the lengths of the two dispersive optical fibers, represents the group velocity dispersion coefficient, represents the angular frequency, Represents the imaginary part.
[0057] Therefore, the optical pulse can be stretched in the time domain through the transfer function of the first section of dispersive optical fiber to achieve pulse broadening.
[0058] The optical pulses passing through the first dispersive medium enter the DPol-DDMZM. Since the DPol-DDMZM is essentially composed of DDMZM based on two polarization states, it receives the microwave signals received by the two antennas respectively, and distributes each microwave signal in two polarization states through a 90-degree phase shift. For each individual DDMZM, the microwave signal received by the antenna also needs to be divided into two paths and enter the two electrical drive ports of the DDMZM, one of which passes through a 90-degree phase shifter to achieve single-sideband modulation of the optical pulse. The purpose of single-sideband modulation is to prevent the microwave signal modulated on the optical carrier from generating power attenuation in the subsequent dispersive medium.
[0059] Assume that the received microwave signal is ,in Indicates the amplitude, Represents the signal angular frequency, which is 90 degrees phase shifted. , then the input of each DDMZM is set to Output As shown in the following formula: ; in, is the phase shift introduced by the bias voltage, is the nth-order Bessel function of the first kind, t is the time, Represents the imaginary part.
[0060] One of the two optical signals output from the dual-polarization dual-drive Mach-Zehnder modulator passes through a 90-degree polarization rotator PR and then is combined by the two signals, and then further stretched in the time domain through a second section of dispersive optical fiber SMF.
[0061] Furthermore, the spectrum of the optical signal in the stretched modulated optical pulse is flattened by the spectrum shaper SS, so as to flatten the spectrum and reduce noise interference. The spectrum shaper can be implemented by a spatial light modulator (such as a WaveShaper). Among them, the WaveShaper is a programmable optical filter.
[0062] The optical signal output by the spectrum shaper SS is divided into two paths by the PBS, which correspond to the two DDMZMs of the DPol-DDMZM. The optical signal is converted into a low-frequency electrical signal by a photoelectric detector.
[0063] Furthermore, the two low-frequency electrical signals are received, de-enveloped and resolved through the DSP module.
[0064] Specifically, suppose the two signals received by the DSP module are and , the actual measured signal AOA is , because the delay of the two microwave signals generated by AOA is set to , we can get , is the speed of light in vacuum, Usually set to , we can get the phase difference of the microwave signals received by the two antennas And the frequency of the microwave signal that needs to be solved in the end and arrival angle It can be shown as follows: ; in, and , and They are and The frequency and phase information, is the stretch multiple.
[0065] In order to facilitate intuitive understanding, the above specific embodiments are simulated and verified. The key simulation parameters are as follows: the input repetition frequency of the optical pulse is 100 MHz (megahertz), the 1 / e half bandwidth is 2000 GHz (gigahertz), and the dispersion coefficient is set (Picoseconds squared divided by the distance in kilometers), the first section of dispersive fiber is 20 km, the second section of dispersive fiber is 180 km, so the stretch factor The modulator coefficient is set to 0.1, the microwave signal to be tested is set to a single-frequency signal with a frequency of 10 GHz and an arrival angle of 30 degrees, and the SS shaping bandwidth is set to 200 GHz. The frequency domain diagram of the received signal after the DSP module removes the envelope is shown in the figure below: Figure 2 As shown, the measured signal frequency is 1 GHz, and the arrival angle is 30.02 degrees. According to the above formula, it can be calculated that the frequency of the microwave signal to be measured is 10 GHz, and the arrival angle is 30.02 degrees, which is only 0.02 degrees different from the true value, and the error is small.
[0066] After the optical pulse is generated by the pulse generation module, the optical pulse is stretched in the time domain by the first dispersion module; further, the stretched optical pulse is modulated by the signal modulation module based on the microwave signal received from the antenna, and the dual-polarization dual-drive Mach-Zehnder modulator therein is used to modulate the stretched optical pulse; so that the modulated optical pulse obtained by modulation can be stretched in the time domain by the second dispersion module; and then the signal detection module is used to detect the stretched modulated optical pulse, and the frequency and arrival angle of the microwave signal can be obtained. By compensating for the RF power attenuation caused by dispersion through modulation, the distortion of the microwave signal can be reduced, and by avoiding the influence of laser power fluctuation and pulse time jitter through time domain stretching, errors can be avoided, thereby improving the stability of signal measurement.
[0067] Figure 3is a flow chart of a signal measurement method provided in an embodiment of the present application, such as Figure 3 As shown, the signal measurement method includes: Step 110: time-domain stretching is performed on the generated optical pulses.
[0068] Step 120, modulating the stretched optical pulse based on the microwave signal received from the antenna.
[0069] Step 130: performing time domain stretching on the modulated optical pulses obtained by modulation.
[0070] Step 140, performing signal detection on the stretched modulated optical pulse to obtain the frequency and arrival angle of the microwave signal.
[0071] It should be noted that the executor of the signal measurement method provided in the embodiment of the present application may be a server, a computer device, etc. The computer device may be, for example, a mobile phone, a tablet computer, a laptop computer, a PDA, a vehicle-mounted electronic device, a wearable device, an ultra-mobile personal computer (UMPC), a netbook, or a personal digital assistant (PDA).
[0072] A signal measuring device may be provided or connected to the server or computer device of the present application, thereby controlling the signal measuring device to execute the signal measuring method of the present application.
[0073] When the signal measurement method of the present application is executed by a signal measurement device, the pulse laser source MLL is controlled to generate an optical pulse and then enter the first dispersion module, so that the optical pulse passes through the first section of dispersion optical fiber SMF for pulse broadening (specifically, time domain stretching) and then enters the optical input port of the dual-polarization dual-drive Mach-Zehnder modulator DPol-DDMZM respectively.
[0074] The microwave signals received by two antennas (antenna 1 and antenna 2) are input to the electrical input port of the dual-polarization dual-drive Mach-Zehnder modulator (the delay of the two microwave signals is set to , we can get , is the speed of light in vacuum, Usually set to , λ represents the wavelength of the microwave signal), one of the electrical signals of each dual-drive Mach-Zehnder modulator DDMZM passes through a 90-degree phase shifter, and single-sideband modulation is achieved by adjusting the bias voltage to work at the orthogonal bias point.
[0075] By using single-sideband modulation to compensate for the RF power attenuation caused by dispersion, time-domain stretching technology can reduce the difficulty of signal acquisition, so that all signals within the frequency band can be collected and analyzed. In this way, multi-frequency signals can be measured and the frequency resolution can be improved by reducing the pulse repetition frequency.
[0076] One of the two optical signals output from the dual-polarization dual-drive Mach-Zehnder modulator is combined by passing through a 90-degree polarization rotator PR, and then further stretched in the time domain through a second section of dispersion optical fiber SMF.
[0077] This application uses time domain stretching technology, which is usually used in large bandwidth frequency measurement. By controlling the dispersion ratio between the front and rear dispersion media, the stretching coefficient can be adjusted, greatly reducing the sampling difficulty and required sampling rate of the DSP module. The influence of laser optical power fluctuation and time jitter is avoided.
[0078] Furthermore, the spectrum is flattened by the spectrum shaper SS, and the optical signal output by the spectrum shaper is divided into two paths by the polarization beam splitter PBS and enters two photodetectors PD for photoelectric conversion to obtain low-frequency electrical signals, which are further analyzed and solved by the digital signal processing module DSP to obtain information such as the frequency and arrival angle of the microwave signal.
[0079] The present application utilizes the above-mentioned signal measurement device to simultaneously realize the functions of wide bandwidth frequency measurement and arrival angle measurement, suppresses microwave signal power attenuation introduced by dispersion through single-sideband modulation, has low requirements on the signal acquisition module, and realizes a simple and easy to integrate device.
[0080] More specifically, in the present application, after the light pulse emitted by the mode-locked laser enters the first section of dispersive optical fiber, it is stretched in the time domain through the dispersive optical fiber.
[0081] It should be noted that, assuming that the two sections of dispersive optical fiber in this application have the same dispersion coefficient, the transfer function and stretch coefficient of the two sections of dispersive optical fiber are As shown in the following formula: ; in, and Respectively represent the lengths of the two dispersive optical fibers, represents the group velocity dispersion coefficient, represents the angular frequency, Represents the imaginary part.
[0082] Therefore, the optical pulse can be stretched in the time domain through the transfer function of the first section of dispersive optical fiber to achieve pulse broadening.
[0083] The optical pulses passing through the first dispersive medium enter the DPol-DDMZM. Since the DPol-DDMZM is essentially composed of DDMZM based on two polarization states, it receives the microwave signals received by the two antennas respectively, and distributes each microwave signal in two polarization states through a 90-degree phase shift. For each individual DDMZM, the microwave signal received by the antenna also needs to be divided into two paths and enter the two electrical drive ports of the DDMZM, one of which passes through a 90-degree phase shifter to achieve single-sideband modulation of the optical pulse. The purpose of single-sideband modulation is to prevent the microwave signal modulated on the optical carrier from generating power attenuation in the subsequent dispersive medium.
[0084] Assume that the received microwave signal is ,in Indicates the amplitude, Represents the signal angular frequency, which is 90 degrees phase shifted. , then the input of each DDMZM is set to Output As shown in the following formula: ; in, is the phase shift introduced by the bias voltage, is the nth-order Bessel function of the first kind, t is the time, Represents the imaginary part.
[0085] One of the two optical signals (modulated optical pulses) output from the dual-polarization dual-drive Mach-Zehnder modulator is polarized by a 90-degree polarization rotator PR, and then the adjusted and unadjusted signals are combined, and after combining, they are further stretched in the time domain by a second section of dispersive optical fiber SMF.
[0086] Furthermore, the spectrum of the optical signal in the stretched modulated optical pulse is flattened by the spectrum shaper SS, so as to flatten the spectrum and reduce noise interference. The spectrum shaper can be implemented by a spatial light modulator (such as a WaveShaper). Among them, the WaveShaper is a programmable optical filter.
[0087] The optical signal output by the spectrum shaper SS is divided into two paths by the PBS, which correspond to the two DDMZMs of the DPol-DDMZM. The optical signal is converted into a low-frequency electrical signal by a photoelectric detector.
[0088] Furthermore, the two low-frequency electrical signals are received, de-enveloped and resolved through the DSP module.
[0089] Specifically, suppose the two signals received by the DSP module are and , the actual measured signal AOA is , because the delay of the two microwave signals generated by AOA is set to , we can get , is the speed of light in vacuum, Usually set to , we can get the phase difference of the microwave signals received by the two antennas And the frequency of the microwave signal that needs to be solved in the end and arrival angle It can be shown as follows: ; in, and , and They are and The frequency and phase information, is the stretch multiple.
[0090] In order to facilitate intuitive understanding, the above specific embodiments are simulated and verified. The key simulation parameters are as follows: the input repetition frequency of the optical pulse is 100 MHz (megahertz), the 1 / e half bandwidth is 2000 GHz (gigahertz), and the dispersion coefficient is set (Picoseconds squared divided by the distance in kilometers), the first section of dispersive fiber is 20 km, the second section of dispersive fiber is 180 km, so the stretch factor The modulator coefficient is set to 0.1, the microwave signal to be tested is set to a single-frequency signal with a frequency of 10 GHz and an arrival angle of 30 degrees, and the SS shaping bandwidth is set to 200 GHz. The frequency domain diagram of the received signal after the DSP module removes the envelope is shown in the figure below: Figure 2 As shown, the measured signal frequency is 1 GHz, and the arrival angle is 30.02 degrees. According to the above formula, it can be calculated that the frequency of the microwave signal to be measured is 10 GHz, and the arrival angle is 30.02 degrees, which is only 0.02 degrees different from the true value, and the error is small.
[0091] According to the signal measurement method of the embodiment of the present application, after the optical pulse is generated by the pulse generation module, the optical pulse is stretched in the time domain by the first dispersion module; further, the stretched optical pulse is modulated by the signal modulation module based on the microwave signal received from the antenna, using the dual-polarization dual-drive Mach-Zehnder modulator therein; so that the modulated optical pulse obtained by modulation can be stretched in the time domain by the second dispersion module; and then the stretched modulated optical pulse is detected by the signal detection module, and the frequency and arrival angle of the microwave signal can be obtained. By compensating for the RF power attenuation caused by dispersion through modulation, the distortion of the microwave signal can be reduced, and by avoiding the influence of laser power fluctuation and pulse time jitter through time domain stretching, errors can be avoided, thereby improving the stability of signal measurement.
[0092] In another aspect, an embodiment of the present application further provides a non-transitory computer storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to perform the methods provided in the above embodiments, for example, including: performing time domain stretching on the generated optical pulses; modulating the stretched optical pulses based on a microwave signal received from an antenna; Performing time domain stretching on the modulated optical pulse obtained by modulation; Signal detection is performed on the stretched modulated light pulse to obtain the frequency and arrival angle of the microwave signal.
[0093] In another aspect, an embodiment of the present application further provides a computer program product having a computer program stored thereon, which is implemented when the computer program is executed by a processor to perform the methods provided in the above embodiments, for example, including: performing time domain stretching on the generated optical pulses; modulating the stretched optical pulses based on a microwave signal received from an antenna; Performing time domain stretching on the modulated optical pulse obtained by modulation; Signal detection is performed on the stretched modulated light pulse to obtain the frequency and arrival angle of the microwave signal.
[0094] 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.
[0095] 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 relevant technology 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 embodiment.
[0096] Finally, it should be noted that the above implementation modes are only used to illustrate the present application, rather than to limit the present application. Although the present application is described in detail with reference to the embodiments, a person skilled in the art should understand that various combinations, modifications or equivalent substitutions of the technical solutions of the present application do not depart from the spirit and scope of the technical solutions of the present application.
Claims
1. A signal measuring device, characterized in that: It includes a pulse generation module, a first dispersion module, a signal modulation module, a second dispersion module and a signal detection module connected in sequence; the signal modulation module includes a dual-polarization dual-drive Mach-Zehnder modulator; The first dispersion module is used to perform time domain stretching on the optical pulse generated by the pulse generation module; The signal modulation module is used to modulate the stretched optical pulse through the dual-polarization dual-drive Mach-Zehnder modulator based on the microwave signal received from the antenna; The second dispersion module is used to perform time domain stretching on the modulated optical pulses obtained by modulation; The signal detection module is used to perform signal detection on the stretched modulated light pulse to obtain the frequency and arrival angle of the microwave signal.
2. The signal measuring device according to claim 1, characterized in that: The signal measuring device further comprises a phase shifter; the dual-polarization dual-drive Mach-Zehnder modulator comprises two dual-drive Mach-Zehnder modulators; The phase shifter is used to phase shift one of the two signals of each microwave signal received from the antenna and then input the phase to the dual-polarization dual-drive Mach-Zehnder modulator; wherein different microwave signals are input to different dual-drive Mach-Zehnder modulators in the dual-polarization dual-drive Mach-Zehnder modulator after phase shift; The dual-drive Mach-Zehnder modulator is used to modulate the stretched optical pulse based on one signal after phase shift and the other signal without phase shift in two signals of the microwave signal.
3. The signal measuring device according to claim 2, characterized in that: The dual-polarization dual-drive Mach-Zehnder modulator also includes a polarization controller; The polarization controller is used to adjust the polarization state of the modulated light pulse output by any of the two dual-driven Mach-Zehnder modulators of the dual-polarization dual-driven Mach-Zehnder modulator.
4. The signal measuring device according to claim 1, characterized in that: The signal detection module includes a spectrum shaper, a polarization beam splitter, a photodetector and a digital signal processing module; The spectrum shaper is used to perform spectrum shaping on the stretched modulated optical pulse to obtain a shaped optical signal; The polarization beam splitter is used to split the shaped optical signal into two paths and enter different photodetectors; The photoelectric detector is used to perform photoelectric conversion on the two optical signals to obtain low-frequency electrical signals; The digital signal processing module is used to analyze the two low-frequency electrical signals to obtain the frequency and arrival angle of the microwave signal.
5. A signal measurement method, characterized in that: include: Performing time-domain stretching on the generated light pulses; modulating the stretched optical pulses based on a microwave signal received from an antenna; Performing time domain stretching on the modulated optical pulse obtained by modulation; Signal detection is performed on the stretched modulated light pulse to obtain the frequency and arrival angle of the microwave signal.
6. The signal measurement method according to claim 5, characterized in that: The method of modulating the stretched optical pulse based on the microwave signal received from the antenna comprises: For two microwave signals received from the antenna, phase shift is performed on one of the two signals of each microwave signal; For each microwave signal, the stretched optical pulse is modulated by the phase-shifted signal and the original signal.
7. The signal measurement method according to claim 6, characterized in that: After modulating the stretched optical pulse by the phase-shifted signal and the original signal for each microwave signal, the method further includes: adjusting the polarization state of any one of the two modulated optical pulses; The modulated optical pulse after polarization state adjustment is combined with another modulated optical pulse.
8. The signal measurement method according to claim 5, characterized in that: The method of performing signal detection on the stretched modulated optical pulse to obtain the frequency and arrival angle of the microwave signal comprises: Performing spectrum shaping on the stretched modulated optical pulse to obtain a shaped optical signal; Splitting the shaped optical signal into two paths and respectively entering the photoelectric detector; Performing photoelectric conversion on the two optical signals respectively to obtain low-frequency electrical signals; The two low-frequency electrical signals are analyzed to obtain the frequency and arrival angle of the microwave signal.
9. A storage medium, the storage medium being a non-transitory computer-readable storage medium, on which a computer program is stored, characterized in that: When the computer program is executed by a processor, the signal measurement method according to any one of claims 5 to 8 is implemented.
10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the signal measurement method according to any one of claims 5 to 8 is implemented.