A microwave photon frequency hopping transmitting and receiving system

Abstract

A microwave photon frequency-hopping transmission and reception system comprises a dual-band, dual-frequency cascaded optical frequency comb module, a transmission carrier generation and signal modulation module, a radio frequency transmission module, an orthogonal optical sampling clock generation module, an electro-optical sampling and orthogonal demultiplexing module, a radio frequency reception module, an optoelectronic conversion and digital processing module, and a synchronization and control module. In the frequency-hopping transmission portion, the communication signal is loaded onto the optical carrier via carrier-suppressed single-sideband modulation. The beat frequency of the optical carrier and the optical comb teeth selected by the optical switch generates an RF transmission signal carrying the communication signal. Rapid switching of the optical switch enables rapid, flexible, and wide-range switching of the transmission carrier frequency. In the frequency-hopping reception portion, the optical comb teeth are selected by the optical switch to generate an orthogonal optical sampling clock. Rapid switching of the optical switch enables rapid, flexible, and wide-range switching of the center frequency of the receiving passband. Flexible configuration of the frequency-hopping reception passband bandwidth is achieved by varying the filter bandwidth.

Description

Technical Field

[0001] The present invention relates to the transmission and reception of frequency hopping communication signals, in particular to the transmission and reception of frequency hopping communication signals with large bandwidth, high frequency point, multiple frequency hopping passbands and flexible configuration. Background Art

[0002] Since the beginning of the 21st century, communication technology has experienced rapid and continuous development, but at the same time, communication systems are facing security challenges. To improve the security, confidentiality, anti-interference, and anti-interception capabilities of communication systems, a series of security technologies are needed. Among them, frequency hopping communication technology is a very effective and important technology.

[0003] Frequency hopping communication refers to a communication method in which the carrier frequency of the communication signal transmitted by the sender and receiver changes discretely according to a predetermined rule. In other words, the carrier frequency used in frequency hopping communication hops under the control of a pseudo-random change code.

[0004] Compared to fixed-frequency communication, because the operating frequency of frequency-hopping communication fluctuates over time, a fixed-frequency communication system can only receive communications within a fixed receive band, making it difficult to intercept all communications. Even if the other party also uses a frequency-hopping communication system, it cannot intercept the entire communication without knowing the encrypted frequency-hopping pattern, thus improving the frequency-hopping communication system's resistance to interception. When part of the communication channel is interfered with, the frequency-hopping communication system can quickly switch to other, uninterrupted channels to continue communication, further enhancing the frequency-hopping communication system's anti-interference capabilities. Furthermore, frequency-hopping communication can be combined with the information encryption technology of fixed-frequency communication to further enhance security and confidentiality. Therefore, compared to fixed-frequency communication, frequency-hopping communication has stronger anti-interference and anti-interception capabilities, providing better security and confidentiality.

[0005] However, the current frequency-hopping communication system based on electronics has encountered an electronic bottleneck. The existing frequency-hopping communication system based on microwave photonics is also limited by the generation limitations of the frequency-hopping local oscillator source and the tuning speed limitations of the tunable filter. The operating frequency, frequency-hopping range, and frequency-hopping switching speed need to be further improved. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned technical problems and proposes a microwave photonic frequency-hopping transmission and reception system that can simultaneously transmit and receive frequency-hopping communication signals with large bandwidth, high frequency, and multiple frequency-hopping passbands. A dual-band, dual-frequency cascaded optical frequency comb module provides a locked optical frequency comb and optical carrier signal for frequency-hopping transmission and reception through dual optical comb cascade. In the frequency-hopping transmission portion, in the transmission carrier generation and signal modulation module, the communication signal is loaded onto the optical carrier through carrier-suppressed single-sideband modulation. The beat frequency of the optical carrier and the optical comb teeth selected by the optical switch generates a radio frequency transmission signal carrying the communication signal. Rapid switching of the optical switch enables rapid, flexible, and wide-range switching of the transmission carrier frequency. In the frequency-hopping reception portion, the orthogonal optical sampling clock generation module generates an orthogonal optical sampling clock by selecting the optical comb teeth of the optical switch. Rapid switching of the optical switch enables rapid, flexible, and wide-range switching of the center frequency of the reception passband. The optoelectronic conversion and digital processing module achieves flexible configuration of the frequency-hopping reception passband bandwidth by changing the bandwidth of the filter. The present invention can effectively improve the system operating frequency, increase the system frequency hopping range and frequency hopping switching speed, and at the same time greatly enhance the tunability and flexibility of the system, and can realize ultra-wideband, fast and flexible frequency hopping transmission and reception according to actual needs.

[0007] To achieve the above objectives, the technical solution of a microwave photon frequency hopping transmitting and receiving system of the present invention is as follows:

[0008] A microwave photon frequency hopping transmitting and receiving system, comprising:

[0009] A dual-band, dual-frequency cascaded optical frequency comb module is used to generate two sets of optical frequency comb signals in different bands with the same comb tooth frequency interval;

[0010] The transmission carrier generation and signal modulation module is used to modulate the communication signal onto the optical carrier and generate the radio frequency transmission signal through the optical comb beat frequency;

[0011] A radio frequency transmitting module, used for transmitting frequency hopping communication signals;

[0012] An orthogonal optical sampling clock generation module is used to generate an orthogonal optical sampling clock to support signal sampling at the frequency hopping receiving end;

[0013] An electro-optical sampling and orthogonal demultiplexing module, used for sampling and demultiplexing received frequency-hopping communication signals;

[0014] A radio frequency receiving module, used for receiving frequency hopping communication signals;

[0015] Optoelectronic conversion and digital processing module, used to convert optical signals into electrical signals and perform digital processing; and

[0016] The synchronization and control module is used for system synchronization and control, providing optical comb selection control signals for the optical switch array to achieve frequency hopping transmission and reception, and realizing synchronous capture and tracking of frequency hopping signals based on the digital signal processing results.

[0017] The dual-band dual-frequency cascaded optical frequency comb module includes:

[0018] A dual-band optical frequency comb generator, configured to generate two sets of optical frequency comb signals, the two sets of optical frequency comb signals being located in band I and band Q, respectively, with the comb teeth having the same frequency spacing;

[0019] The first wave demultiplexer is used to split the optical frequency comb signal into three parts;

[0020] A first optical coupler and a second optical coupler for light splitting;

[0021] a first optical switch array, configured to select optical comb teeth of a specific wavelength band, wherein the frequency interval between the optical comb teeth of wavelength band I output by the first optical switch array and the optical comb teeth of the first portion of optical signals is equal to the frequency interval between the optical comb teeth of wavelength band Q output by the first optical switch array and the optical comb teeth of the third portion of optical signals;

[0022] a first wavelength division multiplexer for combining optical signals;

[0023] an electro-optical frequency comb generating device for generating a new optical frequency comb signal based on the selected optical comb teeth, wherein the comb tooth frequency interval of the two sets of generated optical frequency comb signals is equal to the required frequency hopping frequency interval;

[0024] The transmission carrier generation and signal modulation module includes:

[0025] a first electro-optical modulator, configured to modulate a communication signal onto an optical carrier;

[0026] a second wavelength demultiplexer and a second optical switch array for selecting optical comb teeth of a specific wavelength band;

[0027] a second wavelength division multiplexer for combining the modulated optical signal and the gated optical comb;

[0028] a first photodetector, configured to convert an optical signal into a radio frequency signal;

[0029] The orthogonal optical sampling clock generation module includes:

[0030] a third wavelength demultiplexer and a third optical switch array for selecting optical comb teeth of a specific wavelength band;

[0031] a third wavelength division multiplexer for combining optical signals;

[0032] a phase shifter for performing phase shifting on the optical signal to generate an orthogonal optical sampling clock signal;

[0033] The electro-optical sampling and orthogonal demultiplexing module includes:

[0034] a second electro-optical modulator, configured to perform electro-optical sampling on the received frequency-hopping communication signal;

[0035] A band demultiplexer is used to split the optical signal into two optical signals, band I and band Q;

[0036] The photoelectric conversion and digital processing module includes:

[0037] The second photodetector and the third photodetector are used to convert the optical signal into an electrical signal;

[0038] The first filter and the second filter are used to adjust the bandwidth of the receiving passband;

[0039] a first analog-to-digital converter and a second analog-to-digital converter for converting analog signals into digital signals; a digital signal processor for processing the digital signals and reconstructing the communication signals;

[0040] The synchronization and control module includes relevant devices for synchronization and control.

[0041] Specifically:

[0042] In the dual-band dual-frequency cascade optical frequency comb module, the optical signal generated by the dual-band optical frequency comb generating device is divided into three parts after passing through the first wavelength division multiplexer. The first part is split by the first optical coupler and then input into the transmission carrier generation and signal modulation module and the orthogonal optical sampling clock generation module respectively. The second part is split in sequence by the first optical switch array, the first wavelength division multiplexer, the electro-optical frequency comb generating device and the second optical coupler and then input into the transmission carrier generation and signal modulation module and the orthogonal optical sampling clock generation module respectively. The third part is input into the orthogonal optical sampling clock generation module. In the transmission carrier generation and signal modulation module, the optical signal from the dual-band dual-frequency cascade optical frequency comb module is One optical signal from the first optical coupler is input to the optical input port of the first electro-optical modulator and is electro-optically modulated by the communication signal. The output modulated optical signal enters the second wavelength division multiplexer. At the same time, one optical signal from the second optical coupler in the dual-band dual-frequency cascade optical frequency comb module is also input to the second wavelength division multiplexer after passing through the second wavelength demultiplexer and the second optical switch array in sequence. The two optical signals are combined into one and then input to the first photodetector. The first photodetector outputs a radio frequency signal that is transmitted to the radio frequency transmitting module and emitted into space. In the orthogonal optical sampling clock generation module, another optical signal from the first optical coupler in the dual-band dual-frequency cascade optical frequency comb module is input to the third The wavelength division multiplexer is a device in which another optical signal from the second optical coupler in the dual-band dual-frequency cascade optical frequency comb module is input into the third wavelength division multiplexer after passing through the third wavelength demultiplexer and the third optical switch array. The optical signal from the first wavelength demultiplexer in the dual-band dual-frequency cascade optical frequency comb module is input into the third wavelength division multiplexer through the phase shifter. Finally, the third wavelength division multiplexer outputs an optical signal which enters the electro-optical sampling and orthogonal demultiplexing module. In the electro-optical sampling and orthogonal demultiplexing module, the optical signal is input into the second electro-optical modulator and electro-optically sampled by the received frequency hopping signal from the RF receiving module. The output modulated optical signal enters the wavelength demultiplexer and outputs two optical signals, namely the added optical signal. The uplink optical signal and the downlink optical signal respectively enter the photoelectric conversion and digital processing module; in the photoelectric conversion and digital processing module, the uplink optical signal passes through the second photodetector, the first filter, and the first analog-to-digital converter to enter the digital signal processor, and the downlink optical signal passes through the third photodetector, the second filter, and the second analog-to-digital converter to enter the digital signal processor, and the digital signal processor reconstructs the received communication signal within the passband; the synchronization and control module is respectively connected to the second optical switch array, the third optical switch array, and the digital signal processor, and realizes frequency hopping communication of the transmitting and receiving frequencies by controlling the gating states of the second optical switch array and the third optical switch array.

[0043] In the dual-band dual-frequency cascade optical frequency comb module, the dual-band optical frequency comb generating device generates two sets of optical frequency comb signals located in different bands with the same comb tooth frequency interval, which are respectively recorded as Band I and Band Q.

[0044] In the dual-band, dual-frequency cascaded optical frequency comb module, the first wavelength demultiplexer outputs three optical signals, wherein the first optical signal comprises an optical comb tooth from wavelength band I, and the third optical signal comprises an optical comb tooth from wavelength band Q. The second optical signal is gated by the first optical switch array to output one optical comb tooth from wavelength band I and one optical comb tooth from wavelength band Q. The frequency interval between the optical comb tooth from wavelength band I output by the first optical switch array and the optical comb tooth from the first optical signal is equal to the frequency interval between the optical comb tooth from wavelength band Q output by the first optical switch array and the optical comb tooth from the third optical signal.

[0045] In the dual-band dual-frequency cascaded optical frequency comb module, the electro-optical frequency comb generating device generates two sets of optical frequency comb signals located in band I and band Q with the same comb tooth frequency interval, and the optical comb tooth frequency interval is equal to the required frequency hopping frequency interval.

[0046] In the transmission carrier generation and signal modulation module, the first electro-optical modulator is used to modulate the communication signal onto the optical carrier to achieve carrier suppressed single sideband modulation.

[0047] In the transmission carrier generation and signal modulation module, the second wavelength division multiplexer operates in wavelength band I. Under the control of the synchronization and control module, the second optical switch array selects and outputs an optical comb tooth from wavelength band I. The second wavelength division multiplexer combines the optical signal output by the first electro-optical modulator and the optical signal output by the second optical switch array into one output, which is then transmitted to the first photodetector. The transmitted radio frequency is switched by switching the optical comb tooth selected by the second optical switch array.

[0048] In the orthogonal optical sampling clock generation module, the third optical switch array selects two paths under the control of the synchronization and control module, outputting one optical comb tooth of band I and one optical comb tooth of band Q respectively. The frequency interval between the optical comb tooth of band I output by the third optical switch array and the first part of the optical signal output by the first wavelength division multiplexer is equal to the frequency interval between the optical comb tooth of band Q output by the third optical switch array and the third part of the optical signal output by the first wavelength division multiplexer, which is denoted as f. c .

[0049] In the orthogonal optical sampling clock generation module, the phase shifter performs a 90° phase shift on the input optical signal;

[0050] Each channel of the first optical switch array, the second optical switch array, and the third optical switch array may be composed of a 1×1 optical switch.

[0051] In the electro-optical sampling and orthogonal demultiplexing module, the band demultiplexer outputs two optical signals, which are located in band I and band Q respectively.

[0052] In the photoelectric conversion and digital processing module, the sampling rate of the first analog-to-digital converter and the second analog-to-digital converter is fs is the optical comb tooth interval f in the orthogonal optical sampling clock generation module c The integer factors of f s =f c / N, where N is a positive integer;

[0053] In the photoelectric conversion and digital processing module, the first filter and the second filter have a cutoff frequency less than or equal to f s / 2 low-pass filter or high cutoff frequency less than or equal to f s / 2 bandpass filter;

[0054] The synchronization and control module provides comb selection control signals for the second optical switch array in the transmission carrier generation and signal modulation module and the third optical switch array in the orthogonal optical sampling clock generation module, and realizes synchronous capture and tracking of the frequency hopping signal based on the processing results of the digital signal processor in the photoelectric conversion and digital processing module;

[0055] Frequency hopping receiving system at f = f c There is a receiving passband at the position where the optical comb tooth interval f is rapidly changed by the orthogonal optical sampling clock generation module. c , you can quickly switch the center frequency f of the frequency hopping receiving passband c The bandwidth of the frequency hopping receiving passband is changed by changing the bandwidth of the first filter and the second filter in the photoelectric conversion and digital processing module.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] 1) The present invention can simultaneously realize the transmission and reception of frequency hopping communication signals, and the transmission and reception functions are completely independent, and the transmission frequency and the reception frequency can be different;

[0058] 2) The present invention realizes fast switching of the frequency hopping passband by quickly adjusting the orthogonal optical sampling clock signal, and has extremely fast frequency hopping speed and extremely high configurability.

[0059] 3) The present invention can flexibly adjust the frequency hopping reception range, the number of frequency hopping passbands, the frequency hopping passband bandwidth, the frequency hopping passband amplitude response, etc. according to actual needs, and can adapt to more scenarios.

[0060] 4) The present invention reduces the demand for electrical back-end hardware and can effectively collect high-carrier frequency frequency-hopping communication signals at a lower sampling rate.

[0061] 5) The present invention suppresses image interference through orthogonal sampling, can accurately and effectively distinguish image signals, and realize anti-aliasing digital reception of frequency hopping communication signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a structural diagram of Example 1 of the microwave photon frequency hopping transmitting and receiving system of the present invention.

[0063] Figure 2 It is a schematic diagram of the spectrum of the optical signal in the microwave photon frequency hopping transmitting and receiving system of the present invention.

[0064] Figure 3 It is a structural diagram of embodiment 1 of the optical switch array of the present invention.

[0065] Figure 4 It is a schematic diagram of the frequency hopping communication signal processing process and frequency hopping passband switching in the microwave photon frequency hopping transmitting and receiving system of the present invention.

[0066] Figure 5 It is a schematic diagram of the principle of orthogonal sampling in the microwave photon frequency hopping transmitting and receiving system of the present invention.

[0067] Figure 6 It is a schematic diagram of the principle of signal recovery and image suppression of the orthogonal sampling algorithm in the microwave photon frequency hopping transmission and receiving system of the present invention. DETAILED DESCRIPTION

[0068] The present invention will be further described below in conjunction with examples and drawings. This example is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific workflow. However, the protection scope of the present invention is not limited to the following examples.

[0069] Example 1

[0070] See also Figures 1 to 6 , Figure 1 It is a structural diagram of Example 1 of the microwave photon frequency hopping transmitting and receiving system of the present invention.

[0071] A microwave photon frequency-hopping transmission and reception system comprises: a dual-band dual-frequency cascaded optical frequency comb module A, a transmission carrier generation and signal modulation module B, a radio frequency transmission module C, an orthogonal optical sampling clock generation module D, an electro-optical sampling and orthogonal demultiplexing module E, a radio frequency reception module F, an optoelectronic conversion and digital processing module G, and a synchronization and control module H.

[0072] The dual-band dual-frequency cascade optical frequency comb module A includes a dual-band optical frequency comb generator A1, a first wavelength demultiplexer A2, a first optical coupler A3, a first optical switch array A4, a first wavelength division multiplexer A5, an electro-optical frequency comb generator A6, and a second optical coupler A7. The transmission carrier generation and signal modulation module B includes a first electro-optical modulator B1, a second wavelength demultiplexer B2, a second optical switch array B3, a second wavelength division multiplexer B4 and a first photodetector B5. The radio frequency transmission module C includes a correlation device for transmitting a frequency hopping signal. The orthogonal optical sampling clock generation module D includes a first The three-wavelength demultiplexer D1, the third optical switch array D2, the third wavelength division multiplexer D3 and the phase shifter D4; the electro-optical sampling and orthogonal demultiplexing module E includes a second electro-optical modulator E1 and a band demultiplexer E2; the radio frequency receiving module F includes related devices for receiving frequency hopping signals; the photoelectric conversion and digital processing module G includes a second photodetector G1, a third photodetector G2, a first filter G3, a second filter G4, a first analog-to-digital converter G5, a second analog-to-digital converter G6 and a digital signal processor G7; the synchronization and control module H includes related devices for synchronization and control.

[0073] In the dual-band dual-frequency cascaded optical frequency comb module A, the dual-band optical frequency comb generator A1 generates two sets of optical frequency comb signals in different bands with the same comb tooth frequency interval, which are respectively denoted as Band I and Band Q. Figure 2 FIG is a schematic diagram of the spectrum of the optical signal in the microwave photon frequency hopping transmission and reception system of the present invention. The spectrum of the dual-band optical frequency comb signal is as follows: Figure 2 As shown in OFC 1. The optical signal generated by the dual-band optical frequency comb generator A1 is divided into three parts by the first wavelength demultiplexer A2. The first part of the optical signal contains an optical comb tooth f from band I. I0 After being split by the first optical coupler A3, the optical signals are respectively input into the transmission carrier generation and signal modulation module B and the orthogonal optical sampling clock generation module D. The second part of the optical signal is selected by the first optical switch array A4 to output one optical comb tooth of wavelength band I and one optical comb tooth of wavelength band Q, which are denoted as f I1 and f Q1 , and then enters the electro-optical frequency comb generator A6 after passing through the first wavelength division multiplexer A5. The third part of the optical signal contains an optical comb tooth f from the wavelength band Q. Q0 , directly input into the orthogonal optical sampling clock generating module D. The wavelength band I optical comb f output by the first optical switch array A4 I1 The first part of the light signal light comb f I0 The frequency interval is equal to the wavelength Q optical comb f output by the first optical switch array A4. Q1 The third part of the light signal light comb f Q0 The frequency interval, i.e. |f I1 -fI0 |=|f Q1 -f Q0 |=f start >0. The electro-optical frequency comb generator A6 generates two sets of optical frequency comb signals located in band I and band Q with the same comb tooth frequency interval. The optical comb tooth frequency interval is equal to the required frequency hopping frequency interval, such as Figure 2 As shown in OFC 2, the optical signal output by the electro-optical frequency comb generator A6 is split by the second optical coupler A7 and then input into the transmission carrier generation and signal modulation module B and the orthogonal optical sampling clock generation module D respectively.

[0074] In the transmitting carrier generation and signal modulation module B, the optical signal f from the first optical coupler A3 in the dual-band dual-frequency cascade optical frequency comb module A is I0 The baseband frequency of the communication signal is f sig The communication signal can adopt different code formats. The first electro-optical modulator B1 performs carrier suppressed single sideband modulation to obtain an optical frequency of f I0 +f sig or f I0 -f sig The modulated optical signal output enters the second wavelength division multiplexer B4; at the same time, the optical signal from the second optical coupler A7 in the dual-band dual-frequency cascade optical frequency comb module A is input to the second wavelength demultiplexer B2. The second wavelength demultiplexer B2 operates in wavelength band I. The second optical switch array B3, under the control of the synchronization and control module H, selects and outputs an optical comb tooth from wavelength band I, which can be recorded as f I-TX , the output light comb f I-TX The second wavelength division multiplexer B4 combines the modulated optical signal output by the first electro-optical modulator B1 with the optical signal f output by the second optical switch array B3. I-TX Combined into one output to the first photoelectric detection B5, the frequency hopping communication radio frequency signal to be transmitted is obtained, and the transmission frequency of the frequency hopping communication signal is |f I-TX -f I0 -f sig |or|f I-TX -f I0 +f sig |, and finally transmitted to the RF transmission module C and transmitted into space. The transmitted RF frequency is switched by switching the optical comb teeth selected by the second optical switch array B3.

[0075] In the orthogonal optical sampling clock generation module D, the optical signal f from the first optical coupler A3 in the dual-band dual-frequency cascade optical frequency comb module A is I0The optical signal OFC 2 from the second optical coupler A7 in the dual-band dual-frequency cascade optical frequency comb module A passes through the third wavelength demultiplexer D1 and enters the third optical switch array D2. The third optical switch array D2 selects two paths under the control of the synchronization and control module H, outputting one optical comb tooth each for band I and band Q, i.e., f In and f Qn , and then input into the third wavelength division multiplexer D3; the optical signal f from the first wavelength division multiplexer A2 in the dual-band dual-frequency cascade optical frequency comb module A Q0 After being phase-shifted by 90° by the phase shifter D4, the optical signals are input to the third wavelength division multiplexer D3. Finally, the third wavelength division multiplexer D3 combines and outputs an optical signal, which contains two optical comb teeth from band I and two optical comb teeth from band Q, respectively. I0 、f In 、f Q0 and f Qn , and the comb teeth spacing of the light from band I is equal to the comb teeth spacing of the light from band Q, denoted as |f In -f I0 |=|f Qn -f Q0 |=f cn , the light intensity time domain waveform is the beat frequency f cn The superposition of the single-tone component and the DC component, due to f Q0 The phase is shifted by 90 degrees, so the light intensity time domain waveform envelopes of the two sets of optical sampling clock optical signals are orthogonal to each other. The synchronization and control module H provides control information, which quickly switches the orthogonal optical sampling clock signals with different frequency components through the control information. The corresponding beat frequency component f of the light intensity time domain waveform cn It also switches quickly.

[0076] Each channel of the first optical switch array A4 in the dual-band dual-frequency cascaded optical frequency comb module A, the second optical switch array B3 in the transmission carrier generation and signal modulation module B, and the third optical switch array D2 in the orthogonal optical sampling clock generation module D can be composed of a 1×1 optical switch. Figure 3 It is a structural diagram of embodiment 1 of the optical switch array of the present invention.

[0077] In the electro-optical sampling and orthogonal demultiplexing module E, the optical signal is input to the second electro-optical modulator E1 and electro-optically sampled by the received frequency hopping signal s(t) from the radio frequency receiving module F. The modulated optical signal s is output. M (t) Enter the band demultiplexer E2, which has a wide wavelength division passband and can completely separate the frequency components of band I and band Q to achieve orthogonal demodulation. It ultimately outputs two optical signals, located in band I and band Q respectively, and enters the optoelectronic conversion and digital processing module G.

[0078] In the photoelectric conversion and digital processing module G, the uplink optical signal passes through the second photodetector G1, the first filter G3, and the first analog-to-digital converter G5, and the downlink optical signal passes through the third photodetector G2, the second filter G4, and the second analog-to-digital converter G6. The sampling rates of the first analog-to-digital converter G5 and the second analog-to-digital converter G6 are f s is the optical comb tooth interval f in the orthogonal optical sampling clock generation module D c The integer factors of f s =f c / N, where N is a positive integer; the first filter G3 and the second filter G4 have a cutoff frequency less than or equal to f s / 2 low-pass filter or high cutoff frequency less than or equal to f s / 2 bandpass filter. The two optical signals are photodetected and filtered to obtain two photocurrent signals s E (t), and then the discrete digital signal s is obtained through analog-to-digital conversion ADC (m), where m is a natural number, and finally enters the digital signal processor G7, which processes the discrete digital signal s ADC (m) Perform data processing to reconstruct the received communication signal within the passband.

[0079] The synchronization and control module H provides comb selection control signals to the second optical switch array B3 in the transmission carrier generation and signal modulation module B and the third optical switch array D2 in the orthogonal optical sampling clock generation module D. It also achieves synchronous capture and tracking of frequency-hopping signals based on the processing results of the digital signal processor G7 in the optoelectronic conversion and digital processing module G.

[0080] Figure 4 Schematic diagram of the frequency hopping communication signal processing process and frequency hopping passband switching in the microwave photon frequency hopping transmitting and receiving system of the present invention, wherein Figure 4 (a) corresponds to the above signal processing process. The equivalent channel response of the frequency hopping receiving system can be expressed as

[0081] |H A f|∝|H E (f)+H E (ff cn )|

[0082] Among them, H E (f) is the frequency response of the electrical back-end filter. The first term H E (f) represents the passband at DC f = 0, and the second term H E (ff cn ) represents the position where f=f cnSince the DC component can be easily filtered out, such as by a DC block, a high-pass filter, or a digital filter, only f = f is considered. cn The receiving passband is sufficient.

[0083] Figure 4 (b) shows the signal processing process when switching the center frequency of the frequency hopping reception passband. The synchronization and control module H sends control information to quickly change the optical comb tooth interval f through the orthogonal optical sampling clock generation module D. c , you can quickly switch the center frequency f of the frequency hopping receiving passband c The bandwidth of the frequency hopping receiving passband is changed by changing the bandwidth of the first filter G3 and the second filter G4 in the photoelectric conversion and digital processing module G.

[0084] Figure 5 This is a schematic diagram of the principle of orthogonal sampling in the microwave photon frequency hopping transmission and receiving system of the present invention. As shown in the figure, the waveband I and the waveband Q will obtain the I-path signal and the Q-path signal orthogonal to each other. For the convenience of observation, Figure 5 S of the waveband Q E (f) is the image after being rotated 90°.

[0085] Figure 6 This diagram illustrates the principle of signal recovery and image suppression using the quadrature sampling algorithm in the microwave photonic frequency-hopping transmission and reception system of the present invention. The quadrature sampling algorithm runs in digital signal processor G7 within optoelectronic conversion and digital processing module G. This algorithm then determines the frequency of the frequency-hopping communication and the transmitted information, achieving image suppression and anti-aliasing digital reception.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A microwave photon frequency hopping transmitting and receiving system, characterized in that: It includes a dual-band dual-frequency cascaded optical frequency comb module (A), a transmission carrier generation and signal modulation module (B), a radio frequency transmission module (C), an orthogonal optical sampling clock generation module (D), an electro-optical sampling and orthogonal demultiplexing module (E), a radio frequency receiving module (F), an optoelectronic conversion and digital processing module (G), and a synchronization and control module (H). In the dual-band dual-frequency cascade optical frequency comb module (A), the optical signal generated by the dual-band optical frequency comb generating device (A1) is divided into three parts by the first wavelength division multiplexer (A2); the first part is split by the first optical coupler (A3) and then input into the transmission carrier generation and signal modulation module (B) and the orthogonal optical sampling clock generating module (D); the second part is split by the first optical switch array (A4), the first wavelength division multiplexer (A5), the electro-optical frequency comb generating device (A6) and the second optical coupler (A7) in sequence and then input into the transmission carrier generation and signal modulation module (B) and the orthogonal optical sampling clock generating module (D); the third part is input into the orthogonal optical sampling clock generating module (D); In the transmission carrier generation and signal modulation module (B), one optical signal from the first optical coupler (A3) in the dual-band dual-frequency cascade optical frequency comb module (A) is input into the optical input port of the first electro-optical modulator (B1), and is electro-optically modulated by the communication signal. The output modulated optical signal enters the second wavelength division multiplexer (B4). At the same time, one optical signal from the second optical coupler (A7) in the dual-band dual-frequency cascade optical frequency comb module (A) is sequentially passed through the second wavelength demultiplexer (B2) and the second optical switch array (B3) and then input into the second wavelength division multiplexer (B4). The two optical signals are combined into one and then input into the first photodetector (B5). The first photodetector (B5) outputs a radio frequency signal which is transmitted to the radio frequency transmission module (C) and emitted into space. In the orthogonal optical sampling clock generation module (D), another optical signal from the first optical coupler (A3) in the dual-band dual-frequency cascade optical frequency comb module (A) is input into the third wavelength division multiplexer (D3), another optical signal from the second optical coupler (A7) in the dual-band dual-frequency cascade optical frequency comb module (A) is input into the third wavelength division multiplexer (D3) after passing through the third wavelength demultiplexer (D1) and the third optical switch array (D2), and the optical signal from the first wavelength demultiplexer (A2) in the dual-band dual-frequency cascade optical frequency comb module (A) is input into the third wavelength division multiplexer (D3) through the phase shifter (D4), and finally the third wavelength division multiplexer (D3) outputs an optical signal that enters the electro-optical sampling and orthogonal demultiplexing module (E); In the electro-optical sampling and orthogonal demultiplexing module (E), an optical signal is input into a second electro-optical modulator (E1), and electro-optically sampled by a received frequency-hopping signal from a radio frequency receiving module (F). The output modulated optical signal enters a band demultiplexer (E2), and two optical signals, namely an upstream optical signal and a downstream optical signal, are output, which respectively enter the optoelectronic conversion and digital processing module (G); In the photoelectric conversion and digital processing module (G), the uplink optical signal passes through the second photodetector (G1), the first filter (G3), and the first analog-to-digital converter (G5) and enters the digital signal processor (G7), and the downlink optical signal passes through the third photodetector (G2), the second filter (G4), and the second analog-to-digital converter (G6) and enters the digital signal processor (G7), and the digital signal processor (G7) reconstructs the received communication signal within the passband; The synchronization and control module (H) is respectively connected to the second optical switch array (B3), the third optical switch array (D2) and the digital signal processor (G7), and realizes frequency hopping communication of transmission and reception frequencies by controlling the gating states of the second optical switch array (B3) and the third optical switch array (D2).

2. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the dual-band dual-frequency cascade optical frequency comb module (A), the dual-band optical frequency comb generating device (A1) generates two sets of optical frequency comb signals located in different bands and with the same comb tooth frequency interval, which are respectively recorded as band I and band Q.

3. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the dual-band dual-frequency cascaded optical frequency comb module (A), a first wavelength demultiplexer (A2) outputs three optical signals, wherein the first optical signal comprises an optical comb tooth from wavelength band I, and the third optical signal comprises an optical comb tooth from wavelength band Q. The second optical signal is selected by a first optical switch array (A4) to output one optical comb tooth of wavelength band I and one optical comb tooth of wavelength band Q, wherein the frequency interval between the optical comb tooth of wavelength band I output by the first optical switch array (A4) and the optical comb tooth of the first optical signal is equal to the frequency interval between the optical comb tooth of wavelength band Q output by the first optical switch array (A4) and the optical comb tooth of the third optical signal.

4. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the dual-band dual-frequency cascade optical frequency comb module (A), the electro-optical frequency comb generating device (A6) generates two sets of optical frequency comb signals located in band I and band Q with the same comb tooth frequency interval, and the optical comb tooth frequency interval is equal to the required frequency hopping frequency interval.

5. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the transmission carrier generation and signal modulation module (B), the first electro-optical modulator (B1) is used to modulate the communication signal onto the optical carrier to realize carrier suppressed single sideband modulation.

6. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the transmission carrier generation and signal modulation module (B), the second wavelength division multiplexer (B2) operates in wavelength band I, the second optical switch array (B3) selects and outputs an optical comb tooth from wavelength band I under the control of the synchronization and control module (H), the second wavelength division multiplexer (B4) combines the optical signal output by the first electro-optical modulator (B1) and the optical signal output by the second optical switch array (B3) into one channel and outputs it to the first photodetector (B5), and switches the transmitted radio frequency by switching the optical comb tooth selected by the second optical switch array (B3).

7. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the orthogonal optical sampling clock generation module (D), the third optical switch array (D2) selects two paths under the control of the synchronization and control module (H), outputting one optical comb tooth of waveband I and one optical comb tooth of waveband Q respectively. The frequency interval between the optical comb tooth of waveband I output by the third optical switch array (D2) and the first part of the optical signal output by the first wavelength division multiplexer (A2) is equal to the frequency interval between the optical comb tooth of waveband Q output by the third optical switch array (D2) and the third part of the optical signal output by the first wavelength division multiplexer (A2), which is recorded as f c .

8. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the orthogonal optical sampling clock generation module (D), the phase shifter (D4) performs a 90° phase shift on the input optical signal.

9. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: Each channel of the first optical switch array (A4), the second optical switch array (B3) and the third optical switch array (D2) is composed of a 1×1 optical switch.

10. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the electro-optical sampling and orthogonal demultiplexing module (E), the band demultiplexer (E2) outputs two optical signals, which are located in band I and band Q respectively.

11. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the photoelectric conversion and digital processing module (G), the sampling rate f of the first analog-to-digital converter (G5) and the second analog-to-digital converter (G6) is s is the optical comb tooth interval f in the orthogonal optical sampling clock generation module (D) c The integer factors of f s =f c / N, where N is a positive integer.

12. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: In the photoelectric conversion and digital processing module (G), the first filter (G3) and the second filter (G4) have a cutoff frequency less than or equal to f s / 2 low-pass filter or high cutoff frequency less than or equal to f s / 2 bandpass filter.

13. The microwave photon frequency hopping transmitting and receiving system according to claim 1, characterized in that: The synchronization and control module (H) provides comb selection control signals for the second optical switch array (B3) in the transmission carrier generation and signal modulation module (B) and the third optical switch array (D2) in the orthogonal optical sampling clock generation module (D), and realizes synchronous capture and tracking of frequency hopping signals based on the processing results of the digital signal processor (G7) in the photoelectric conversion and digital processing module (G).

14. The microwave photon frequency hopping transmitting and receiving system according to any one of claims 1 to 13, characterized in that: Frequency hopping receiving system at f = f c There is a receiving passband at the position where the optical comb tooth interval f is rapidly changed by the orthogonal optical sampling clock generation module (D). c , you can quickly switch the center frequency f of the frequency hopping receiving passband c The bandwidth of the frequency hopping reception passband is changed by changing the bandwidth of the first filter (G3) and the second filter (G4) in the photoelectric conversion and digital processing module (G).

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