Novel distributed optical fiber sound wave signal acquisition equipment and method

Abstract

The invention discloses a novel distributed optical fiber acoustic signal acquisition device and method, a control module of the acquisition device comprises an ADC acquisition module, a PWM module, a programmable logic end and a processing system end, and the ADC acquisition module receives ADC data transmitted by an ADC processor and is sequentially connected with the programmable logic end and the processing system end for signal processing; the PWM module is connected with the radio frequency device and the power amplifier in sequence to output a high-voltage pulse modulation signal; the clock module comprises a clock synchronizer and a crystal oscillator and is driven by the control module to generate a first clock signal and a second clock signal which are in the same phase and different in frequency. A first clock signal is respectively input into the PWM module and the frequency mixer, and a second clock signal is respectively input into the ADC acquisition module and the ADC processor. According to the method, coherent fading noise can be reduced, the signal-to-noise ratio of the system is improved, the phi-OTDR system has a high-fidelity vibration signal, meanwhile, the sound wave signal reduction degree can be improved, and the distributed optical fiber vibration capture response time can be shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of distributed optical fiber acoustic wave sensing detection, and in particular to a novel distributed optical fiber acoustic wave signal acquisition device and method. Background Art

[0002] The statements here only provide background technology related to the present invention and do not necessarily constitute prior art. The heterodyne coherent detection type φ-OTDR system uses a narrow linewidth light source with high coherence, and there is a coherent fading situation, which makes the system unable to accurately demodulate the signal vibration information during the monitoring process, resulting in false alarms. The initial phase of the original beat frequency signal collected by the traditional heterodyne coherent φ-OTDR system will drift over time, resulting in a gradual decrease in the correlation between adjacent curves of the continuously collected beat frequency signal. The sliding average processing of the vibration curve will reduce the signal-to-noise ratio.

[0003] In addition, the distributed fiber optic acoustic wave signal acquisition card currently on the market only completes the I / Q demodulation function, and the demodulated data is transmitted to the computer through the PCI-e bus. The entire vibration data analysis and phase data analysis all rely on computer processing, which brings great data processing pressure to the host computer program and places particularly high performance requirements on the computer. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and to provide a novel distributed optical fiber acoustic wave signal acquisition device and method, which can reduce coherent fading noise, improve the system signal-to-noise ratio, and enable the φ-OTDR system to have a high-fidelity vibration signal, while improving the acoustic wave signal restoration degree and distributed optical fiber vibration capture response time.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] On the one hand, the technical solution of the present invention provides a novel distributed optical fiber acoustic wave signal acquisition device, including: a control module, a clock module, an ADC processor, a mixer and a power amplifier;

[0007] Among them, the control module includes an ADC acquisition module, a PWM module, a programmable logic end and a processing system end. The ADC acquisition module receives ADC data transmitted by the ADC processor and is connected to the programmable logic end and the processing system end in sequence for signal processing; the PWM module is connected to the radio frequency device and the power amplifier in sequence to output a high-voltage pulse modulation signal; the clock module includes a clock synchronizer and a crystal oscillator, and is driven by the control module to generate two first clock signals and second clock signals with the same phase but different frequencies; the first clock signal is respectively input into the PWM module and the mixer, and the second clock signal is respectively input into the ADC acquisition module and the ADC processor.

[0008] In at least one embodiment, the programmable logic end includes an I / Q demodulation functional module and a data analysis functional module; the processing system end includes a signal framing functional module and a TCP / IP data processing module; the programmable logic end and the processing system end perform data transmission via AXI bus data.

[0009] In at least one embodiment, the I / Q demodulation function module includes a DDS module, which uses a first clock signal to generate a cosine I / Q demodulation carrier signal and a sine I / Q demodulation carrier signal, which are multiplied with ADC data in a multiplier, and filtered in a FIR low-pass filter to obtain I data and Q data.

[0010] In at least one embodiment, the data analysis function module includes a vibration data analysis module and a phase data analysis module; the signal framing function module includes a vibration signal framing module and a phase signal framing module.

[0011] In at least one embodiment, the control module is also connected and communicated with the storage module and the Gigabit network port respectively.

[0012] In at least one embodiment, the programmable logic end also includes a configuration parameter processing module, and the processing system end includes a configuration parameter frame module; the configuration parameter frame module receives the configuration parameters transmitted by the computer end and parses them to obtain the configuration parameter content, and the configuration parameter content is transmitted to the configuration parameter processing module via the AXI bus for processing.

[0013] On the other hand, the technical solution of the present invention also provides a novel distributed optical fiber acoustic wave signal acquisition method, comprising:

[0014] The programmable logic end of the control module drives the clock synchronizer to output two first clock signals and two second clock signals with the same phase but different frequencies respectively;

[0015] The programmable logic end uses a first clock signal to drive the PWM module to generate a trigger pulse signal;

[0016] The trigger pulse signal and another first clock signal are connected to the mixer together to generate a low-voltage pulse modulation signal, which is then output through a power amplifier and connected to the acousto-optic modulator.

[0017] The programmable logic end uses a second clock signal to drive the ADC processor to collect the beat frequency signal in real time; the programmable logic end uses another second clock signal to drive the ADC acquisition module to collect ADC data.

[0018] In at least one embodiment, further comprising:

[0019] The programmable logic end uses the first clock signal to generate a cosine I / Q demodulation carrier signal and a sine I / Q demodulation carrier signal required by the I / Q demodulation function module respectively;

[0020] Performing I / Q demodulation on the beat frequency signal using a cosine I / Q demodulation carrier signal and a sine I / Q demodulation carrier signal to obtain I data and Q data;

[0021] The amplitude of I data and Q data is calculated to demodulate the vibration signal, and the vibration signal is analyzed to obtain vibration data;

[0022] The inverse tangent of the I data and the Q data is calculated to demodulate the phase signal, and the phase signal is analyzed to obtain the phase data;

[0023] The vibration data and phase data are transmitted to the processing system via the AXI bus, and the processing system forms vibration signal frames and phase signal frames and transmits them to the computer via the TCP / IP protocol.

[0024] In at least one embodiment, analyzing the vibration signal to obtain the vibration data specifically includes: the programmable logic end performs bandpass filtering, first moving average, moving difference and second moving average processing on the demodulated vibration signal to obtain the vibration data.

[0025] In at least one embodiment, analyzing the phase signal to obtain phase data is specifically as follows: the programmable logic end performs range expansion, random initial phase elimination, spatial unwrapping, temporal unwrapping, DC removal and sliding average processing on the demodulated phase signal to obtain the phase data.

[0026] The beneficial effects of the technical solution of the present invention are as follows:

[0027] 1) A novel distributed optical fiber acoustic wave signal acquisition device and method of the present invention uses an 80Mhz clock to generate a trigger pulse. The trigger pulse and the 80Mhz clock enter a mixer, and then are output as a high-voltage pulse modulation signal through a power amplifier, and finally connected to an acousto-optic modulator, so that the beat frequency signals collected by the ADC chip all have the same initial phase, which can reduce coherent fading noise, thereby improving the system signal-to-noise ratio, so that the φ-OTDR system can reconstruct a vibration signal with high frame preservation even in a fading area.

[0028] 2) A novel distributed optical fiber acoustic wave signal acquisition device and method of the present invention uses carrier signals cos80Mhz and sin80Mhz with the same frequency and phase as the high-voltage pulse modulation signal to perform I / Q demodulation on the beat frequency signal, solving the problem of phase imbalance after I / Q demodulation and making the acoustic wave signal more restored.

[0029] 3) A novel distributed optical fiber acoustic wave signal acquisition device and method of the present invention realizes I / Q demodulation, vibration signal analysis and phase signal analysis through the PL end of the ZYNQ chip. The PS end transmits the vibration signal frame and the phase signal frame to the computer through the TCP / IP protocol, which reduces the pressure of data processing on the computer end and improves the time for capturing and restoring distributed optical fiber vibration signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1 This is a schematic diagram of the internal connection of a novel distributed optical fiber acoustic wave signal acquisition device of the present invention;

[0032] Figure 2 It is a schematic diagram of the internal data flow processing of a ZYNQ chip of a novel distributed optical fiber acoustic wave signal acquisition device of the present invention;

[0033] Figure 3 It is a schematic diagram of the internal functional modules of the ZYNQ chip of a novel distributed optical fiber acoustic wave signal acquisition device of the present invention;

[0034] Figure 4 The present invention is a structural diagram of an external differential coherent φ-OTDR system suitable for a novel distributed optical fiber acoustic wave signal acquisition device. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0036] PWM: Pulse Width Modulation, a technology that controls the power to the load by adjusting the width of the pulse (that is, the duration of the pulse). By adjusting the width of the pulse, that is, adjusting the length of time the signal is in a high level state, the average value of the current in the circuit is controlled.

[0037] ADC: Analog-to-digital converter, a device that converts analog signals into digital signals. The conversion of analog signals to digital signals is completed through two main processes: sampling and quantization. The sampling process is to sample the continuous analog signal at a fixed time interval, while quantization is to convert the sampled signal value into the closest digital value.

[0038] As introduced in the background technology, the purpose of the present invention is to overcome the deficiencies existing in the above-mentioned prior art and to provide a new type of distributed optical fiber acoustic wave signal acquisition equipment and method, which can reduce coherent fading noise, improve the system signal-to-noise ratio, and enable the φ-OTDR system to have a high-fidelity vibration signal, while improving the acoustic wave signal restoration degree and distributed optical fiber vibration capture response time.

[0039] Example 1

[0040] like Figure 4 The structure diagram of the external differential coherent φ-OTDR system shown in the figure uses a narrow linewidth fiber laser (NL) as the light source, and the output light is divided into reference light (10%) and signal light (90%) through a 90:10 fiber coupler. The signal light is modulated into pulse light by an acousto-optic modulator (AOM), wherein the modulation end of the acousto-optic modulator is connected to the high-voltage pulse modulation signal output by the acquisition device (DAQ). The pulse light is amplified by an erbium-doped fiber amplifier (EDFA) and enters the sensing fiber through a circulator. The Rayleigh scattered light returned by the sensing fiber and the reference light generate a beat signal in a 50:50 fiber coupler. The beat signal is converted into an electrical signal by a balanced photodetector (BPD). The acquisition device collects and processes the beat signal, and finally transmits the vibration and phase data to a computer (PC).

[0041] In a typical embodiment of the present invention, Figure 1 As shown, this embodiment discloses a novel distributed optical fiber acoustic wave signal acquisition device, which is applied to a heterodyne coherent detection type φ-OTDR system, including: a control module, a clock module, an ADC processor, a mixer and a power amplifier; wherein the control module includes an ADC acquisition module, a PWM module, a programmable logic terminal (i.e., a PL terminal) and a processing system terminal (i.e., a PS terminal), the ADC acquisition module receives ADC data transmitted by the ADC processor and is sequentially connected to the PL terminal and the PS terminal for signal processing; the PWM module is sequentially connected to the radio frequency device and the power amplifier to output a high-voltage pulse modulation signal; the clock module includes a clock synchronizer and a crystal oscillator, and is driven by the control module to generate two first clock signals and second clock signals with the same phase but different frequencies; the first clock signal is respectively input to the PWM module and the mixer, and the second clock signal is respectively input to the ADC acquisition module and the ADC processor.

[0042] In this embodiment, the control module adopts a ZYNQ chip, the ADC processor adopts an ADC chip, and the crystal oscillator adopts an 80Mhz crystal oscillator as the clock source of the clock synchronizer; the first clock signal is an 80Mhz clock signal, the second clock signal is a 240Mhz clock signal, and the first clock signal and the second clock signal are in phase.

[0043] In this embodiment, the PL end of the control module drives the clock synchronizer to output two 80Mhz clock signals and two 240Mhz clock signals in phase through the SPI bus. One of the two 80Mhz clock signals drives the PWM module to generate a trigger pulse signal input to the mixer, and the other 80Mhz clock signal is input to the mixer to generate a low-voltage pulse modulation signal with the trigger pulse signal. The low-voltage pulse modulation signal passes through the power amplifier to output a high-voltage pulse modulation signal to the acousto-optic modulator. One of the two 240Mhz clock signals drives the ADC chip to collect the beat frequency signal, and the other 240Mhz clock signal drives the ADC acquisition module to collect the ADC data transmitted by the ADC chip.

[0044] like Figure 2 and Figure 3 As shown, in this embodiment, the PL end includes an I / Q demodulation function module and a data analysis function module, the PS end includes a signal framing function module and a TCP / IP data processing module, and data is transmitted between the PL end and the PS end via the AXI bus data. The ADC data is demodulated by the I / Q demodulation function module to obtain IQ two-way data, and the vibration data analysis and phase data analysis processing are performed by the data analysis function module to obtain vibration data and phase data respectively, and the vibration data and phase data are transmitted to the signal framing function module of the PS end via the AXI bus to perform vibration signal framing and phase signal framing to obtain vibration signal frames and phase signal frames respectively, and then transmitted to the computer via the TCP / IP data processing module.

[0045] Specifically, the I / Q demodulation function module includes a DDS module, and the DDS module uses the first clock signal 80Mhz clock signal to generate the cosine I / Q demodulation carrier signal cos80Mhz and the sine I / Q demodulation carrier signal sin80Mhz required by the I / Q demodulation function module, and cos80Mhz and sin80Mhz are respectively multiplied with the ADC data in the multiplier, and are filtered in the FIR low-pass filter to obtain I data and Q data. The data analysis function module includes a vibration data analysis module and a phase data analysis module, in which the amplitude of I data and Q data is calculated to obtain a vibration signal, and the vibration signal is successively subjected to bandpass filtering, first moving average, moving difference and second moving average processing to obtain vibration data, and the inverse tangent of I data and Q data is calculated in the phase data analysis module to obtain a phase signal, and the phase signal is successively subjected to range expansion, initial phase elimination, spatial unwrapping, time unwrapping, DC removal and sliding average processing to obtain phase data.

[0046] The signal framing function module at the PS end includes a vibration signal framing module and a phase signal framing module. The vibration data is transmitted from the PL end to the signal framing function module at the PS end via the AXI bus, where the vibration signal is framed to obtain a vibration signal frame, and then transmitted to the computer via the TCP / IP protocol in the TCP / IP data processing module; the phase data is transmitted from the PL end to the signal framing function module at the PS end via the AXI bus, where the phase signal is framed to obtain a phase signal frame, and then transmitted to the computer via the TCP / IP protocol in the TCP / IP data processing module.

[0047] In this embodiment, the control module ZYNQ chip is also connected and communicated with the storage module and the Gigabit Ethernet port respectively. Among them, the storage module includes an SD card and a DDR3 memory for storing programs and data. The Gigabit Ethernet port uses a Gigabit Ethernet port PHY chip, which can ensure the correct and high-speed communication between the ZYNQ chip and the computer end. At the same time, the acquisition device uses a Gigabit Ethernet port communication to have better flexibility, and can flexibly connect to a notebook or tablet computer. The requirements for the performance of the computer host are not high, which can solve the problem that the existing technology uses the PCI-E bus connection method to connect only to a desktop computer, resulting in high requirements for the performance of the computer host. .

[0048] In this embodiment, the PS end of the ZYNQ chip also includes a configuration parameter frame module, and the PL end includes a configuration parameter processing module. The computer end transmits the configuration parameters to the configuration parameter frame module of the PS end through the TCP / IP protocol of the TCP / IP data processing module for parsing and processing, and obtains five configuration parameter contents of laser scanning frequency, PWM pulse width, optical fiber length, data sampling depth and vibration point information. The PS end transmits the obtained configuration parameter contents to the configuration parameter processing module of the PL end through the AXI bus. The PL end determines the period and frequency of the PWM pulse signal output by the PWM module through the laser scanning frequency and PWM pulse width parameters, determines the number of ADC data collected by the ADC acquisition module each time through the optical fiber length and data sampling depth, and determines the phase data analysis module to extract the corresponding phase data through the vibration point position.

[0049] Example 2

[0050] In a typical implementation of the present invention, this embodiment discloses a novel distributed optical fiber acoustic wave signal acquisition method, comprising:

[0051] Step 1: The PL end of the ZYNQ chip of the control module drives the clock synchronizer through the SPI bus, and outputs two 80Mhz clock signals and two 240Mhz clock signals of the same phase respectively;

[0052] Step 2: The PL end of the ZYNQ chip of the control module uses an 80Mhz clock signal to drive the PWM module to generate a trigger pulse signal;

[0053] Step 3: The trigger pulse signal and another 80Mhz clock signal are connected to the mixer to generate a low-voltage pulse modulation signal, which is then output through the power amplifier to generate a high-voltage pulse modulation signal;

[0054] Step 4: The high-voltage pulse modulation signal is connected to the acousto-optic modulator, enters the erbium-doped fiber amplifier, and enters the sensing fiber through the fiber circulator port 2, such as Figure 4 As shown;

[0055] Step 5: The Rayleigh reflected light output from port 3 of the optical fiber circulator and the reference light output from the laser via the optical splitter are connected to the balanced photodetector through the optical fiber coupler. The beat frequency signal output by the balanced photodetector is connected to the ADC processor end of the acquisition device, such as Figure 2 As shown;

[0056] Step 6: The PL end of the ZYNQ chip of the control module uses a 240Mhz clock signal to drive the ADC processor to collect the beat frequency signal in real time; the PL end uses another 240Mhz clock signal to drive the ADC acquisition module to collect ADC data;

[0057] Step 7: The PL end of the ZYNQ chip of the control module uses an 80Mhz clock signal to drive the DDS module to generate the cosine I / Q demodulation carrier signal cos80Mhz and the sine I / Q demodulation carrier signal sin80Mhz required by the I / Q demodulation function module. The cos80Mhz and sin80Mhz are multiplied with the collected ADC data in the multiplier, and filtered in the FIR low-pass filter to obtain I data and Q data respectively.

[0058] Step 8: Calculate the amplitude of I data and Q data to demodulate the vibration signal, and analyze the vibration signal to obtain vibration data; Specifically: the vibration data analysis function module first calculates the square sum and then the square root of the I data and Q data to obtain the vibration signal, and performs band-pass filtering, first moving average, moving difference and second moving average processing on the vibration signal in sequence to obtain vibration data;

[0059] Step 9: Calculate the inverse tangent of the I data and Q data to demodulate the phase signal, and analyze the phase signal to obtain the phase data; specifically, the phase data analysis function module performs inverse tangent calculation on the I data and Q data to obtain the phase signal, and sequentially performs range expansion, initial phase elimination, spatial unwrapping, temporal unwrapping, DC removal and sliding average processing on the phase signal to obtain the phase data;

[0060] Step 10: The PL end transmits the vibration data to the PS end through the AXI bus, performs vibration signal framing processing in the vibration signal framing module of the PS end, obtains the vibration signal frame and transmits it to the computer through the TCP / IP protocol of the TCP / IP data processing module;

[0061] Step 11: The PL end transmits the phase data to the PS end through the AXI bus, performs phase signal framing processing in the phase signal framing module of the PS end, obtains the phase signal frame and transmits it to the computer through the TCP / IP protocol of the TCP / IP data processing module;

[0062] Among them, the computer end transmits the configuration parameters to the configuration parameter frame module of the PS end of the ZYNQ chip through the TCP / IP protocol for parsing and processing, and obtains the five configuration parameter contents of laser scanning frequency, PWM pulse width, optical fiber length, data sampling depth and vibration point information. The PS end transmits the obtained configuration parameter contents to the configuration parameter processing module of the PL end of the ZYNQ chip through the AXI bus. The PL end determines the period and frequency of the PWM pulse signal output by the PWM module through the laser scanning frequency and PWM pulse width parameters, determines the number of ADC data collected by the ADC acquisition module each time through the optical fiber length and data sampling depth, and determines the phase data analysis module to extract the corresponding phase data through the vibration point position.

[0063] The present invention provides a novel distributed optical fiber acoustic wave signal acquisition device and method. A trigger pulse signal is generated by using an 80Mhz clock signal. The trigger pulse signal and the 80Mhz clock signal are connected to a mixer together, and then output as a high-voltage pulse modulation signal through a power amplifier. Finally, the signal is connected to an acousto-optic modulator, so that the beat frequency signals collected by the ADC processor all have the same initial phase, which can reduce coherent fading noise, thereby improving the system signal-to-noise ratio, so that the φ-OTDR system can reconstruct a vibration signal with high fidelity even in a fading area; by using a carrier signal cos80Mhz and a high-voltage pulse modulation signal with the same frequency and phase, the φ-OTDR system can reconstruct a vibration signal with high fidelity even in a fading area; sin80Mhz performs I / Q demodulation on the beat frequency signal, which solves the problem of unclear phase signal demodulation and poor sensitivity caused by phase imbalance after I / Q demodulation, making the acoustic signal restoration degree higher; I / Q demodulation, vibration signal analysis and phase signal analysis processing are realized through the PL end of the control module ZYNQ chip, and the vibration signal frame and phase signal frame are transmitted to the computer through the TCP / IP protocol through the PS end, which reduces the data processing pressure of the distributed optical fiber acoustic wave detection host, reduces the performance requirements of the detection host, and improves the response time of distributed optical fiber vibration capture, which is conducive to the development of portable distributed optical fiber acoustic wave detection system.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A new type of distributed optical fiber acoustic wave signal acquisition equipment, characterized in that: include: Control module, clock module, ADC processor, mixer and power amplifier; Among them, the control module includes an ADC acquisition module, a PWM module, a programmable logic end and a processing system end. The ADC acquisition module receives ADC data transmitted by the ADC processor and is connected to the programmable logic end and the processing system end in sequence for signal processing; the PWM module is connected to the radio frequency device and the power amplifier in sequence to output a high-voltage pulse modulation signal; the clock module includes a clock synchronizer and a crystal oscillator, and is driven by the control module to generate two first clock signals and second clock signals with the same phase but different frequencies; the first clock signal is respectively input into the PWM module and the mixer, and the second clock signal is respectively input into the ADC acquisition module and the ADC processor.

2. A novel distributed optical fiber acoustic wave signal acquisition device as claimed in claim 1, characterized in that: The programmable logic end includes an I / Q demodulation function module and a data analysis function module; the processing system end includes a signal framing function module and a TCP / IP data processing module; the programmable logic end and the processing system end perform data transmission via AXI bus data.

3. A novel distributed optical fiber acoustic wave signal acquisition device as claimed in claim 2, characterized in that: The I / Q demodulation function module includes a DDS module, which uses a first clock signal to generate a cosine I / Q demodulation carrier signal and a sine I / Q demodulation carrier signal, which are multiplied with ADC data in a multiplier respectively, and filtered in a FIR low-pass filter to obtain I data and Q data respectively.

4. A novel distributed optical fiber acoustic wave signal acquisition device as claimed in claim 2, characterized in that: The data analysis function module includes a vibration data analysis module and a phase data analysis module; the signal framing function module includes a vibration signal framing module and a phase signal framing module.

5. A novel distributed optical fiber acoustic wave signal acquisition device as claimed in claim 1, characterized in that: The control module is also connected and communicated with the storage module and the gigabit network port respectively.

6. A novel distributed optical fiber acoustic wave signal acquisition device as claimed in claim 1, characterized in that: The programmable logic end also includes a configuration parameter processing module, and the processing system end includes a configuration parameter frame module; the configuration parameter frame module receives the configuration parameters transmitted by the computer end and parses them to obtain the configuration parameter content, and the configuration parameter content is transmitted to the configuration parameter processing module via the AXI bus for processing.

7. A novel distributed optical fiber acoustic wave signal acquisition method, characterized in that: include: The programmable logic end of the control module drives the clock synchronizer to output two first clock signals and two second clock signals with the same phase but different frequencies respectively; The programmable logic end uses a first clock signal to drive the PWM module to generate a trigger pulse signal; The trigger pulse signal and another first clock signal are connected to the mixer together to generate a low-voltage pulse modulation signal, which is then output through a power amplifier and connected to the acousto-optic modulator. The programmable logic end uses a second clock signal to drive the ADC processor to collect the beat frequency signal in real time; The programmable logic end uses another second clock signal to drive the ADC acquisition module to collect ADC data.

8. A novel distributed optical fiber acoustic wave signal acquisition method as claimed in claim 7, characterized in that: include: The programmable logic end uses the first clock signal to generate a cosine I / Q demodulation carrier signal and a sine I / Q demodulation carrier signal required by the I / Q demodulation function module respectively; Performing I / Q demodulation on the beat frequency signal using a cosine I / Q demodulation carrier signal and a sine I / Q demodulation carrier signal to obtain I data and Q data; The amplitude of I data and Q data is calculated to demodulate the vibration signal, and the vibration signal is analyzed to obtain vibration data; Demodulate the I data and Q data by taking the inverse tangent to obtain the phase signal, and analyze the phase signal to obtain the phase data; The vibration data and phase data are transmitted to the processing system via the AXI bus, and the processing system forms vibration signal frames and phase signal frames and transmits them to the computer via the TCP / IP protocol.

9. A novel distributed optical fiber acoustic wave signal acquisition method as claimed in claim 8, characterized in that: Analyzing the vibration signal to obtain the vibration data is specifically as follows: the programmable logic end performs bandpass filtering, first moving average, moving difference and second moving average processing on the demodulated vibration signal to obtain the vibration data.

10. A novel distributed optical fiber acoustic wave signal acquisition method as claimed in claim 8, characterized in that: The specific steps of analyzing the phase signal to obtain the phase data are as follows: the programmable logic end performs range expansion, random initial phase elimination, spatial unwrapping, temporal unwrapping, DC removal and sliding average processing on the demodulated phase signal to obtain the phase data.

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