A broadband signal Doppler frequency shift system and processing method

Abstract

The present invention discloses a broadband signal Doppler frequency shift system and processing method, belonging to the field of broadband radio frequency signal processing technology, the system includes a multi-channel light wave generating unit, a photoelectric conversion unit, and N optical processing units including a radio frequency signal input end; the processing method includes the multi-channel light wave generating unit outputting one local oscillator light and N parallel direct current lights; one local oscillator light is input to the photoelectric conversion unit, each direct current light is input to a corresponding optical processing unit and converted into an optical signal; the converted output N optical signals are then input to the photoelectric conversion unit and converted into frequency shift signals with the input local oscillator light. The present invention modulates multiple radio frequency signals on light waves, uses optical technology to simultaneously perform coherent processing on multiple modulated optical signals, and then obtains multiple Doppler frequency shift signals output in series by photoelectric conversion, which has obvious advantages in terms of performance level, implementation architecture, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of broadband radio frequency signal processing, and in particular relates to a broadband signal Doppler frequency shift system and a processing method. Background Art

[0002] Electronic warfare equipment processes and receives external threat radar signals and generates effective jamming signals, thereby achieving the function of countering the target. For pulse Doppler radar, in order to destroy its normal tracking function, electronic warfare equipment needs to have precise jamming capabilities in the speed dimension. This requires that electronic warfare equipment must perform Doppler frequency shift on the received broadband radar signal within a reasonable platform movement speed range to ensure that the generated jamming signal can enter the radar to achieve effective suppression or deception effects.

[0003] At present, electronic warfare equipment mainly realizes the jamming signal generation function through digital radio frequency memory (DRFM). The digital radio frequency memory first converts the received radio frequency signal into an intermediate frequency signal, performs analog-to-digital conversion on the intermediate frequency signal, then performs Doppler frequency shift processing on the digital signal in the digital processor, and then converts the intermediate frequency signal into an radio frequency signal through digital-to-analog conversion. Due to the limitation of digital processing capabilities, the instantaneous bandwidth of the digital radio frequency memory is limited (typical value is 1GHz), and it can only process a single narrowband intermediate frequency signal in a period of time, and cannot process multiple received broadband radio frequency signals at the same time, and the response time is slow (typical value is 200ns). Therefore, there are many problems with the digital radio frequency memory in broadband multi-target interference.

[0004] Therefore, the present invention provides a broadband signal Doppler frequency shift system and processing method to at least solve some of the above technical problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a broadband signal Doppler frequency shift system and a processing method to solve the existing technical problems.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A broadband signal Doppler frequency shift system comprises a multi-channel light wave generating unit, a photoelectric conversion unit, and N optical processing units including a radio frequency signal input end, wherein the multi-channel light wave generating unit comprises a local oscillator light output end and N direct current light output ends, the N direct current light output ends are respectively connected to the N optical processing units, and the output ends of the N optical processing units and the local oscillator light output ends are both connected to the optical signal conversion unit.

[0008] Furthermore, the multi-channel light wave generating unit includes a laser, a 1×2 optical coupler A connected to the laser, and a 1×N optical coupler A connected to the 1×2 optical coupler A, the 1×2 optical coupler A includes a first output end and a second output end, the first output end is the local oscillator light output end, the second output end is connected to the 1×N optical coupler A, and the 1×N optical coupler A includes N DC light output ends.

[0009] Furthermore, the optical processing unit includes an optical intensity modulator connected to the DC light output end, an optical filter connected to the optical intensity modulator, and an optical phase modulator connected to the optical filter, and the optical intensity modulator includes a radio frequency signal input end.

[0010] Furthermore, the photoelectric conversion unit includes a 1×N optical coupler B connected to the light intensity modulator, a 1×2 optical coupler B connected to the local oscillator light output end and the 1×N optical coupler B, and a photodetector connected to the 1×2 optical coupler B.

[0011] A method for processing a broadband signal Doppler frequency shift system comprises the following steps:

[0012] Step 1, a multi-channel light wave generating unit outputs one channel of local oscillator light and N channels of parallel direct current light;

[0013] Step 2: One local oscillator light is input to the photoelectric conversion unit, and each DC light is input to a corresponding optical processing unit to be converted into an optical signal;

[0014] Step 3: The N optical signals outputted by the conversion are inputted into the photoelectric conversion unit and converted into frequency-shifted signals together with the input local oscillator light.

[0015] Furthermore, in step 1, the laser light emitted by the laser passes through the 1×2 optical coupler A and is divided into two signals: one is directly output as a local oscillator light signal; the other is input to the 1×N optical coupler A to output N DC light signals with equal power.

[0016] Furthermore, the powers of the two signals output by the 1×2 optical coupler A are equal.

[0017] Furthermore, in step 2, each DC light is input to a corresponding optical intensity modulator, and is subjected to double-sideband intensity modulation via the radio frequency signal simultaneously input to the optical intensity modulator, and then is output to the optical phase modulator after the optical carrier and the modulated lower sideband are filtered out by the optical filter, and then is phase modulated via the control signal simultaneously input to the optical phase modulator, and is output as a corresponding optical signal.

[0018] Furthermore, in step 3, the N optical signals output in parallel by the N optical phase modulators are input into the 1×N optical coupler B to be coupled into a synthetic optical signal, and then input into the 1×2 optical coupler B and the local oscillator light output by the 1×2 optical coupler A to be superimposed and beat, and finally converted into N frequency-shifted signals by the photodetector.

[0019] Furthermore, the N frequency-shifted signals are output in series.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention modulates multiple broadband radio frequency signals on light waves, uses optical technology to simultaneously perform coherent processing on multiple modulated optical signals, and finally obtains multiple Doppler frequency shift signals output in series by photoelectric conversion. The method proposed by the present invention can simultaneously perform Doppler frequency shift on multiple radio frequency signals in a large instantaneous frequency range, and has obvious advantages in terms of performance level, implementation architecture, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the present invention.

[0023] Figure 2 It is a structural schematic diagram of the multi-channel light wave generating unit of the present invention.

[0024] Figure 3 It is a structural schematic diagram of the light processing unit of the present invention.

[0025] Figure 4 It is a schematic structural diagram of the photoelectric conversion unit of the present invention.

[0026] Figure 5 This is a diagram of phase change outputted by an embodiment of the optical phase modulator using a typical positive Doppler shift frequency according to the present invention.

[0027] Figure 6 This is a diagram of phase change outputted by an embodiment of the optical phase modulator using a typical negative Doppler shift frequency according to the present invention.

[0028] The names corresponding to the reference numerals are:

[0029] 1-multi-channel light wave generating unit, 2-optical processing unit, 3-photoelectric conversion unit, 11-laser, 12-1×2 optical coupler A, 13-1×N optical coupler A, 21-light intensity modulator, 22-optical filter, 23-optical phase modulator, 31-1×N optical coupler B, 32-1×2 optical coupler B, 33-photodetector. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "A" and "B" are only used for descriptive purposes and for distinguishing between various structures, and cannot be understood as indicating or implying relative importance.

[0031] like Figure 1-4 As shown, the present invention provides a broadband signal Doppler frequency shift system, comprising a multi-channel light wave generating unit 1, a photoelectric conversion unit 3, and N optical processing units 2 including a radio frequency signal input end, wherein the multi-channel light wave generating unit 1 comprises a local oscillator light output end and N direct current light output ends, the N direct current light output ends are respectively connected to the N optical processing units 2, and the output ends of the N optical processing units 2 and the local oscillator light output ends are both connected to the optical signal conversion unit 3.

[0032] The system of the present invention modulates multiple broadband radio frequency signals on light waves, uses optical technology to simultaneously perform coherent processing on multiple modulated light signals, and finally obtains multiple Doppler frequency shift signals for serial output by photoelectric conversion.

[0033] In some embodiments, the multi-path light wave generating unit includes a laser 11, a 1×2 optical coupler A12 connected to the laser, and a 1×N optical coupler A13 connected to the 1×2 optical coupler A12, the 1×2 optical coupler A12 includes a first output end and a second output end, the first output end is the local oscillator light output end, the second output end is connected to the 1×N optical coupler A13, and the 1×N optical coupler A13 includes N DC light output ends.

[0034] In some embodiments, the optical processing unit 2 includes an optical intensity modulator 21 connected to the DC light output end, an optical filter 22 connected to the optical intensity modulator 21, and an optical phase modulator 23 connected to the optical filter 22, and the optical intensity modulator 21 includes a radio frequency signal input end.

[0035] Each optical intensity modulator 21 inputs a corresponding broadband RF signal for double-sideband intensity modulation of a DC light input thereto, and then the modulated signal is input into the optical filter 22 for filtering, and then input into the optical phase modulator 23 for phase modulation, and each optical phase modulator 23 inputs a corresponding control signal for phase modulation.

[0036] In some embodiments, the photoelectric conversion unit 3 includes a 1×N optical coupler B31 connected to the light intensity modulator 21, a 1×2 optical coupler B32 connected to the local oscillator light output end and the 1×N optical coupler B31, and a photodetector 33 connected to the 1×2 optical coupler B32. The 1×N optical coupler B31 is used for coupling N optical signals output by N optical processing units 2, the 1×2 optical coupler B32 is used for superposition and beat difference of optical signals and local oscillator light signals, and the photodetector 33 is used for output of frequency-shifted signals.

[0037] A method for processing a broadband signal Doppler frequency shift system comprises the following steps:

[0038] Step 1, a multi-channel light wave generating unit outputs one channel of local oscillator light and N channels of parallel direct current light;

[0039] Step 2: One local oscillator light is input to the photoelectric conversion unit, and each DC light is input to a corresponding optical processing unit and converted into an optical signal;

[0040] Step 3: The N optical signals converted and output are then input into the photoelectric conversion unit and converted into frequency-shifted signals together with the input local oscillator light.

[0041] In step 1, the laser light emitted by the laser passes through the 1×2 optical coupler A and is divided into two signals: one is directly output as a local oscillator optical signal; the other is input to the 1×N optical coupler A to output N DC optical signals with equal power. Furthermore, the power of the two signals output by the 1×2 optical coupler A is equal.

[0042] In step 2, each DC light is input to a corresponding optical intensity modulator, and is subjected to double-sideband intensity modulation by the radio frequency signal simultaneously input to the optical intensity modulator, and then is output to the optical phase modulator after the optical carrier and the modulated lower sideband are filtered out by the optical filter, and then is subjected to phase modulation by the control signal simultaneously input to the optical phase modulator, and is output as a corresponding optical signal. Furthermore, the radio frequency signal is a broadband radio frequency signal.

[0043] In step 3, the N optical signals outputted in parallel by the N optical phase modulators are inputted into the 1×N optical coupler B to be coupled into a synthetic optical signal, and then inputted into the 1×2 optical coupler B to be superimposed and beat with the local oscillator light outputted by the 1×2 optical coupler A, and finally converted into N frequency-shifted signals by the photodetector. Furthermore, the N frequency-shifted signals are serially outputted.

[0044] Figure 5This is a phase change diagram of the output of an embodiment of the optical phase modulator using a typical positive Doppler shift in the present invention. The optical phase modulator performs phase modulation on the input single-sideband modulated optical signal. When the control signal increases linearly with time, the output phase of the optical phase modulator will also increase linearly with time. During the change period, the output optical phase increases linearly from 0 to 2π, and the Doppler shift of the output RF signal is the ratio of the phase change slope to 2π, which is a positive Doppler shift.

[0045] Figure 6 This is a phase change diagram of the output of an embodiment of the optical phase modulator using a typical negative Doppler shift in the present invention. The optical phase modulator performs phase modulation on the input single-sideband modulated optical signal. When the control signal decreases linearly with time, the output phase of the optical phase modulator will also decrease linearly with time. During the change period, the output optical phase decreases linearly from 2π to 0, and the Doppler shift of the output RF signal is the ratio of the phase change slope to 2π, which is a negative Doppler shift.

[0046] When the system has actual requirements for Doppler shift frequency in different time periods, it can be based on Figure 5 and Figure 6 The phase change waveform is designed in a corresponding combination to achieve an effective phase control signal.

[0047] The laser 11, 1×2 optical coupler, 1×N optical coupler, light intensity modulator 21, optical filter 22, optical phase modulator 23 and photodetector 33 used in the present invention are all existing known electrical devices and can be directly purchased and used on the market. Their structures, circuits, and control principles are all existing known technologies. Therefore, the structures, circuits, and control principles of the laser 11, 1×2 optical coupler, 1×N optical coupler, light intensity modulator 21, optical filter 22, optical phase modulator 23 and photodetector 33 are not described in detail here.

[0048] Finally, it should be noted that the above embodiments are only preferred embodiments of the present invention to illustrate the technical solutions of the present invention, rather than limiting them, and certainly not limiting the patent scope of the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. In other words, any changes or modifications made to the main design concept and spirit of the present invention that have no substantive significance, and the technical problems they solve are still consistent with the present invention, should be included in the protection scope of the present invention. In addition, the direct or indirect application of the technical solutions of the present invention in other related technical fields is also included in the patent protection scope of the present invention.

Claims

1. A broadband signal Doppler frequency shift system, characterized in that: It includes a multi-channel light wave generating unit, a photoelectric conversion unit, and N light processing units including a radio frequency signal input end, wherein the multi-channel light wave generating unit includes a local oscillator light output end and N direct current light output ends, the N direct current light output ends are respectively connected to the N light processing units, and the output ends of the N light processing units and the local oscillator light output ends are both connected to the photoelectric conversion unit; The multi-path light wave generating unit includes a laser, a 1×2 optical coupler A connected to the laser, and a 1×N optical coupler A connected to the 1×2 optical coupler A, the 1×2 optical coupler A includes a first output end and a second output end, the first output end is the local oscillator light output end, the second output end is connected to the 1×N optical coupler A, and the 1×N optical coupler A includes N direct current light output ends; The optical processing unit includes an optical intensity modulator connected to the DC light output terminal, an optical filter connected to the optical intensity modulator, and an optical phase modulator connected to the optical filter, wherein the optical intensity modulator includes an RF signal input terminal; The photoelectric conversion unit includes a 1×N optical coupler B connected to the light intensity modulator, a 1×2 optical coupler B connected to the local oscillator light output end and the 1×N optical coupler B, and a photodetector connected to the 1×2 optical coupler B.

2. A method for processing a broadband signal Doppler frequency shift system, characterized in that: A broadband signal Doppler frequency shift system as claimed in claim 1, comprising the following steps: Step 1, a multi-channel light wave generating unit outputs one channel of local oscillator light and N channels of parallel direct current light; Step 2: One local oscillator light is input to the photoelectric conversion unit, and each DC light is input to a corresponding optical processing unit and converted into an optical signal; Step 3: The N optical signals converted and output are then input into the photoelectric conversion unit and converted into frequency-shifted signals together with the input local oscillator light.

3. The method for processing a broadband signal Doppler frequency shift system according to claim 2, characterized in that: In step 1, the laser light emitted by the laser passes through the 1×2 optical coupler A and is divided into two signals: one is directly output as a local oscillator light signal; the other is input to the 1×N optical coupler A to output N DC light signals with equal power.

4. The method for processing a broadband signal Doppler frequency shift system according to claim 3, characterized in that: The powers of the two signals output by the 1×2 optical coupler A are equal.

5. The method for processing a broadband signal Doppler frequency shift system according to claim 3, characterized in that: In step 2, each DC light is input to a corresponding optical intensity modulator, and is subjected to double-sideband intensity modulation by the radio frequency signal simultaneously input to the optical intensity modulator, and then the optical carrier and the modulated lower sideband are filtered out by the optical filter and output to the optical phase modulator, and then phase modulated by the control signal simultaneously input to the optical phase modulator, and the output is a corresponding optical signal.

6. The method for processing a broadband signal Doppler frequency shift system according to claim 5, characterized in that: In step 3, the N optical signals output in parallel by the N optical phase modulators are input into the 1×N optical coupler B to be coupled into a synthetic optical signal, and then input into the 1×2 optical coupler B to be superimposed and beat with the local oscillator light output by the 1×2 optical coupler A, and finally converted into N frequency-shifted signals by the photodetector.

7. The method for processing a wideband signal Doppler frequency shift system according to claim 6, characterized in that: The N frequency-shifted signals are output in series.

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