Instantaneous frequency measurement system and method based on phase modulator

Abstract

The invention provides an instantaneous frequency measurement system and method based on a phase modulator, and the system is connected with a vector network analyzer, and comprises a light source module which is used for providing an optical carrier; the modulation module is used for modulating the fed radio frequency microwave signal onto an optical carrier to obtain an optical modulation signal; the wavelength division multiplexing module is used for separating positive and negative first-order sidebands of the optical modulation signal into a first optical modulation signal and a second optical modulation signal; the detection module is used for respectively converting the first light modulation signal and the second light modulation signal into a first electric signal and a second electric signal; the coupling module is used for combining the first electric signal and the second electric signal to form an output electric signal; wherein the vector network analyzer is respectively connected with the modulation module and the coupling module, and the vector network analyzer receives the output electric signal, obtains a power spectrum of the output electric signal and reversely deduces instantaneous frequency information of the radio frequency microwave signal. The system is high in integration level and strong in anti-electromagnetic interference capability, and is suitable for various scenes.

Description

Technical Field

[0001] The present invention relates to the field of microwave photonics, and particularly to an instantaneous frequency measurement system and a measurement method based on a phase modulator. Background Art

[0002] Microwave frequency measurement is an important technology in fields such as communication. Traditional microwave frequency measurement technologies mainly rely on electronic devices to achieve microwave measurement, but traditional microwave frequency measurement technologies face problems such as limited measurement frequency bands, large volume, and poor anti-electromagnetic interference ability.

[0003] High frequency measurement accuracy and wide frequency measurement range are the goals pursued by technicians. However, there is a mutually restrictive relationship between frequency measurement accuracy and frequency measurement range. Different application scenarios have different emphases on the above two indicators. For example, in some wide frequency band ranges, how to use a simple method to measure unknown frequency information and feedback it to other processing systems for response. Currently, existing microwave signal frequency measurement systems generally have problems such as complex structures, large volume and weight, and unstable working states of modulators. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] Aiming at the above deficiencies, the main purpose of the present invention is to provide an instantaneous frequency measurement system and a measurement method based on a phase modulator. The system has high integration and high reliability, the working frequency range of the system is greatly increased, and it has strong anti-electromagnetic interference ability, and can meet the application requirements of various scenarios.

[0006] (2) Technical Solutions

[0007] To achieve the above purpose, in the first aspect of the present invention, an instantaneous frequency measurement system based on a phase modulator is provided, which is connected to a vector network analyzer. The instantaneous frequency measurement system includes: a light source module for providing an optical carrier; a modulation module for modulating the fed radio frequency microwave signal onto the optical carrier to obtain an optical modulation signal; a wavelength division multiplexing module for separating the positive and negative first-order sidebands of the optical modulation signal into a first optical modulation signal and a second optical modulation signal; a detection module for respectively converting the first optical modulation signal and the second optical modulation signal into a first electrical signal and a second electrical signal; a coupling module for combining the first electrical signal and the second electrical signal to form an output electrical signal; wherein, the vector network analyzer is respectively connected to the modulation module and the coupling module. The vector network analyzer receives the output electrical signal, obtains the power spectrum of the output electrical signal, and inversely deduces the instantaneous frequency information of the radio frequency microwave signal fed into the modulation module through the power spectrum of the output electrical signal.

[0008] In the above solution, the light source module includes: a light source for emitting an optical signal; a polarization controller for adjusting the polarization state of the optical signal to obtain an optical carrier.

[0009] In the above solution, the modulation module uses a phase modulator, and the optical modulation signal carries positive and negative first-order sidebands.

[0010] In the above solution, the wavelength division multiplexing module uses a two-channel wavelength division multiplexer.

[0011] In the above solution, the detection module includes two photodetectors connected in parallel, which are used to beat the first optical modulation signal and the second optical modulation signal and convert them into a first electrical signal and a second electrical signal.

[0012] In the above solution, the coupling module uses a 90-degree electrical coupler, which is used to introduce a 90-degree phase shift into the first electrical signal, and after combining the first electrical signal with the 90-degree phase shift and the second electrical signal, an output electrical signal is formed.

[0013] In the second aspect of the present invention, a method for measuring instantaneous frequency is provided. The method includes: obtaining an optical signal; adjusting the polarization state of the optical signal to obtain an optical carrier; feeding a radio frequency microwave signal through a vector network analyzer and modulating it onto the optical carrier to obtain an optical modulation signal; separating the positive and negative first-order sidebands of the optical modulation signal into a first optical modulation signal and a second optical modulation signal; respectively converting the first optical modulation signal and the second optical modulation signal into a first electrical signal and a second electrical signal; combining the first electrical signal and the second electrical signal to form an output electrical signal; receiving the output electrical signal through a vector network analyzer to obtain the power spectrum of the output electrical signal, and inversely deducing the instantaneous frequency information of the fed radio frequency microwave signal through the power spectrum of the output electrical signal.

[0014] (III) Beneficial effects

[0015] The technical solution of the embodiment of the present invention has at least the following beneficial effects:

[0016] (1) The instantaneous frequency measurement system based on a phase modulator proposed by the present invention has high integration, a simple structure, and a small system volume.

[0017] (2) The present invention introduces the advantages of large bandwidth and anti-electromagnetic interference of photon technology. Compared with traditional microwave technology, the optoelectronic integration greatly increases the system operating frequency range and has strong anti-electromagnetic interference ability.

[0018] (3) In the instantaneous frequency measurement system based on a phase modulator proposed by the present invention, a phase modulator is used to avoid the problem of bias point offset. The system structure is simple and reliable, and it can adapt to the application requirements of various scenarios; changing the filter bandwidth can change the system measurement accuracy and measurement range, and the system has strong reconfigurability. Description of the drawings

[0019] Figure 1 Schematically shows the structure diagram of the instantaneous frequency measurement system based on a phase modulator according to an embodiment of the present invention;

[0020] Figure 2 Schematically shows the spectrogram of the output electrical signal according to an embodiment of the present invention;

[0021] Figure 3 Schematically shows the flowchart of the instantaneous frequency measurement method according to an embodiment of the present invention.

[0022] [Description of reference numerals]

[0023] 1 - Light source module; 2 - Modulation module; 3 - Wavelength division multiplexing module; 4 - Detection module; 5 - Coupling module; 11 - Light source; 12 - Polarization controller. Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0025] Please specifically refer to Figure 1 , Figure 1 Schematically shows the structural diagram of the instantaneous frequency measurement system based on a phase modulator according to an embodiment of the present invention.

[0026] As Figure 1 shown, an instantaneous frequency measurement system based on a phase modulator is connected to a vector network analyzer. The instantaneous frequency measurement system includes: a light source module 1 for providing an optical carrier; a modulation module 2 for modulating the fed radio frequency microwave signal onto the optical carrier to obtain an optical modulation signal; a wavelength division multiplexing module 3 for separating the positive and negative first-order sidebands of the optical modulation signal into a first optical modulation signal and a second optical modulation signal; a detection module 4 for respectively converting the first optical modulation signal and the second optical modulation signal into a first electrical signal and a second electrical signal; a coupling module 5 for combining the first electrical signal and the second electrical signal to form an output electrical signal. Among them, the vector network analyzer is respectively connected to the modulation module 2 and the coupling module 5. The vector network analyzer receives the output electrical signal, obtains the power spectrum of the output electrical signal, and inversely deduces the instantaneous frequency information of the radio frequency microwave signal fed into the modulation module 2 through the power spectrum of the output electrical signal.

[0027] Specifically, please continue to refer to Figure 1 , the light source module 1 includes: a light source 11 for emitting an optical signal; a polarization controller 12 for adjusting the polarization state of the optical signal to obtain an optical carrier. For example, in this embodiment, the wavelength of the optical carrier is 1552.52 nm.

[0028] In an embodiment of the present invention, the modulation module 2 uses a phase modulator. The phase modulator modulates a preset microwave signal onto the optical carrier to obtain an optical modulation signal; wherein, the optical modulation signal carries positive and negative first-order sidebands.

[0029] In an embodiment of the present invention, the wavelength division multiplexing module 3 adopts a dual-channel wavelength division multiplexer with a filtering bandwidth of 50 GHz. The dual-channel wavelength division multiplexer divides the optical modulation signal with positive and negative first-order sidebands into a first optical modulation signal and a second optical modulation signal.

[0030] It should be noted that the first optical modulation signal is a positive first-order optical modulation signal, and the second optical modulation signal is a negative first-order optical modulation signal, or the first optical modulation signal is a negative first-order modulation optical signal, and the second optical modulation signal is a positive first-order modulation optical signal.

[0031] In an embodiment of the present invention, the detection module 4 includes two parallel photodetectors, which are used to beat the first optical modulation signal and the second optical modulation signal and convert them into a first electrical signal and a second electrical signal.

[0032] In an embodiment of the present invention, the coupling module 5 adopts a 90-degree electrical coupler, which is used to introduce a 90-degree phase shift into the first electrical signal. After combining the first electrical signal with the 90-degree phase shift and the second electrical signal, an output electrical signal is formed.

[0033] In an embodiment of the present invention, the vector network analyzer receives the output electrical signal, obtains the power spectrum of the output electrical signal, and inversely deduces the frequency information of the radio frequency microwave signal fed into the system.

[0034] For example, in this embodiment, the radio frequency microwave signal (electrical signal) fed into the system is a signal with 40 equally spaced frequency points from 0 to 40 GHz; after inputting this system, the final output electrical signal spectrum is obtained.

[0035] Figure 2 Schematically shows the spectrum diagram of the output electrical signal according to an embodiment of the present invention. As Figure 2 shown, it can be found that the output electrical signal spectrum is a function of the input frequency signal. Therefore, in this system, the modulation module can also obtain the microwave signal fed in externally through the interface, and inversely deduce the instantaneous frequency information of the radio frequency microwave signal through the output electrical signal power spectrum to complete the measurement of the microwave signal frequency.

[0036] Through the embodiment of the present invention, the instantaneous frequency measurement system based on the phase modulator has strong anti-electromagnetic interference ability. Using the phase modulator can avoid the problem of bias point offset. The system structure is simple and reliable, and it can meet the application requirements of various scenarios; changing the filtering bandwidth can change the measurement accuracy and measurement range of the system, and the system has strong reconfigurability.

[0037] Based on the above instantaneous frequency measurement system, the present invention also provides an instantaneous frequency measurement method.

[0038] Figure 3 Schematically shows the flowchart of the instantaneous frequency measurement method according to an embodiment of the present invention.

[0039] Please refer specifically to Figure 3 , the method further includes operations S110 to S170.

[0040] In operation S110, an optical signal is acquired;

[0041] In operation S120, the polarization state of the optical signal is adjusted to obtain an optical carrier;

[0042] In operation S130, a radio frequency microwave signal is fed through a vector network analyzer and modulated onto the optical carrier to obtain an optical modulation signal;

[0043] In operation S140, the positive and negative first-order sidebands of the optical modulation signal are separated into a first optical modulation signal and a second optical modulation signal;

[0044] In operation S150, the first optical modulation signal and the second optical modulation signal are respectively converted into a first electrical signal and a second electrical signal;

[0045] In operation S160, the first electrical signal and the second electrical signal are combined to form an output electrical signal;

[0046] In operation S170, the output electrical signal power spectrum is obtained by receiving the output electrical signal through a vector network analyzer, and the instantaneous frequency information of the fed radio frequency microwave signal is deduced back through the output electrical signal power spectrum.

[0047] In summary, the present invention provides an instantaneous frequency measurement system and measurement method based on a phase modulator. The system has high integration and high reliability, introducing the advantages of large bandwidth and anti-electromagnetic interference of photon technology. Compared with traditional microwave technology in optoelectronic integration, the operating frequency range of the system is greatly increased, and the anti-electromagnetic interference ability is strong, capable of adapting to the application requirements of various scenarios.

[0048] Those skilled in the art can understand that although the present invention has been shown and described with reference to specific exemplary embodiments of the present invention, those skilled in the art should understand that various changes in form and detail can be made to the present invention without departing from the spirit and scope of the present invention defined by the appended claims and their equivalents. Therefore, the scope of the present invention should not be limited to the above embodiments, but should be determined not only by the appended claims but also by the equivalents of the appended claims.

[0049] Similarly, it should be understood that, for the purpose of streamlining the present invention and facilitating the understanding of one or more of the various disclosed aspects, in the foregoing description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the foregoing claims, the disclosed aspects lie in less than all of the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate embodiment of the present invention.

[0050] The above specific embodiments have further elaborated on the object, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. An instantaneous frequency measurement system based on a phase modulator, connected to a vector network analyzer, characterized in that The instantaneous frequency measurement system includes: A light source module (1) for providing an optical carrier; A modulation module (2) for modulating the fed radio frequency microwave signal onto the optical carrier to obtain an optical modulation signal; A wavelength division multiplexing module (3) for separating the positive and negative first-order sidebands of the optical modulation signal into a first optical modulation signal and a second optical modulation signal; A detection module (4) for respectively converting the first optical modulation signal and the second optical modulation signal into a first electrical signal and a second electrical signal; A coupling module (5) for combining the first electrical signal and the second electrical signal to form an output electrical signal; Wherein, the vector network analyzer is respectively connected to the modulation module (2) and the coupling module (5), the vector network analyzer receives the output electrical signal, obtains the power spectrum of the output electrical signal, and infers the instantaneous frequency information of the radio frequency microwave signal fed into the modulation module (2) through the power spectrum of the output electrical signal.

2. The instantaneous frequency measurement system according to claim 1, characterized in that The light source module (1) includes: A light source (11) for emitting an optical signal; A polarization controller (12) for adjusting the polarization state of the optical signal to obtain the optical carrier.

3. The instantaneous frequency measurement system according to claim 1, characterized in that, The modulation module (2) uses a phase modulator, and the optical modulation signal has positive and negative first-order sidebands.

4. The instantaneous frequency measurement system according to claim 2, wherein The wavelength division multiplexing module (3) uses a two-channel wavelength division multiplexer.

5. The instantaneous frequency measurement system according to claim 1, characterized in that The detection module (4) includes two parallel photodetectors for beating the first optical modulation signal and the second optical modulation signal and converting them into a first electrical signal and a second electrical signal.

6. The instantaneous frequency measurement system according to claim 1, wherein The coupling module (5) uses a 90-degree electrical coupler for introducing a 90-degree phase shift into the first electrical signal, and combining the first electrical signal with the 90-degree phase shift and the second electrical signal to form the output electrical signal.

7. A method for measuring instantaneous frequency, characterized in that, The method includes: Obtaining an optical signal; Adjusting the polarization state of the optical signal to obtain an optical carrier; Feeding a radio frequency microwave signal through a vector network analyzer and modulating it onto the optical carrier to obtain an optical modulation signal; Separating the positive and negative first-order sidebands of the optical modulation signal into a first optical modulation signal and a second optical modulation signal; Respectively converting the first optical modulation signal and the second optical modulation signal into a first electrical signal and a second electrical signal; Combining the first electrical signal and the second electrical signal to form an output electrical signal; Receiving the output electrical signal through a vector network analyzer to obtain the power spectrum of the output electrical signal, and inferring the instantaneous frequency information of the fed radio frequency microwave signal through the power spectrum of the output electrical signal.

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