A new type of distributed optical fiber sound wave signal acquisition device and method

Abstract

The application discloses a novel distributed optical fiber sound wave signal collection device and method, and the control module of the collection device comprises an ADC collection module, a PWM module, a programmable logic end and a processing system end; the ADC collection 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 sequentially connected with a radio frequency device and a power amplifier to output a high-voltage pulse modulation signal; a clock module comprises a clock synchronizer and a crystal oscillator, and two kinds of first clock signals and second clock signals with the same phase and different frequencies are generated by driving the control module; the first clock signals are input into the PWM module and a frequency mixer respectively, and the second clock signals are input into the ADC collection module and the ADC processor respectively. The application can reduce coherent fading noise, improve the signal-to-noise ratio of the system, make the phi-OTDR system have high-fidelity vibration signals, and improve the sound wave signal restoration degree and the response time of the distributed optical fiber vibration capture.

Description

Technical Field

[0001] This invention relates to the field of distributed fiber optic acoustic wave sensing and detection technology, specifically to a novel distributed fiber optic acoustic wave signal acquisition device and method. Background Technology

[0002] The statements herein provide only background information related to this invention and do not necessarily constitute prior art. Heterodyne coherent detection φ-OTDR systems use highly coherent, narrow-linewidth light sources, which suffer from coherent fading. This prevents the system from accurately demodulating signal vibration information during monitoring, leading to false alarms. Furthermore, the initial phase of the raw beat frequency signal acquired by a traditional heterodyne coherent φ-OTDR system drifts over time, causing a gradual decrease in the correlation between adjacent beat frequency curves in continuously acquired signals. Moving average processing of the vibration curves can actually reduce the signal-to-noise ratio.

[0003] Furthermore, currently available distributed fiber optic acoustic signal acquisition cards only perform I / Q demodulation, and the demodulated data is transmitted to the computer via the PCI-e bus. The entire vibration and phase data analysis process relies on the computer, placing a significant data processing burden on the host computer program and placing extremely high demands on the computer's performance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a novel distributed optical fiber acoustic signal acquisition device and method, which can reduce coherent fading noise, improve the system signal-to-noise ratio, enable the φ-OTDR system to have a high-fidelity vibration signal, and at the same time improve the acoustic signal fidelity and the distributed optical fiber vibration capture response time.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

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

[0007] The control module includes an ADC acquisition module, a PWM module, a programmable logic terminal, and a processing system terminal. The ADC acquisition module receives ADC data transmitted by the ADC processor and is sequentially connected to the programmable logic terminal and the processing system 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, which are driven by the control module to generate two clock signals, a first clock signal and a second clock signal, that are in phase but have different frequencies. The first clock signal is input to the PWM module and the mixer, and the second clock signal is input to the ADC acquisition module and the ADC processor, respectively.

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

[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 an FIR low-pass filter to obtain I data and Q data, respectively.

[0010] In at least one embodiment, the data parsing function module includes a vibration data parsing module and a phase data parsing 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 to and communicates with the storage module and the gigabit network port, respectively.

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

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

[0014] The programmable logic terminal of the control module drives the clock synchronizer to output two first clock signals and two second clock signals that are in phase but have different frequencies.

[0015] The programmable logic terminal 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 fed into the mixer to generate a low-voltage pulse modulation signal, which is then output as a high-voltage pulse modulation signal by the power amplifier and connected to the acousto-optic modulator.

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

[0018] In at least one embodiment, it further includes:

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

[0020] The beat frequency signal is demodulated using cosine I / Q demodulation carrier signal and sine I / Q demodulation carrier signal to obtain I data and Q data;

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

[0022] The phase signal is extracted by calculating the arctangent of the I and Q data, and the phase data is obtained by analyzing the phase signal.

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

[0024] In at least one embodiment, obtaining vibration data by parsing the vibration signal specifically involves: the programmable logic terminal performing bandpass filtering, first moving average, moving differential, and second moving average processing on the demodulated vibration signal to obtain vibration data.

[0025] In at least one embodiment, obtaining phase data by parsing the phase signal specifically involves: the programmable logic terminal performing value range expansion, random initial phase elimination, spatial unwinding, temporal unwinding, DC removal, and moving average processing on the demodulated phase signal to obtain phase data.

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

[0027] 1) The novel distributed optical fiber acoustic 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 the output is a high-voltage pulse modulation signal through a power amplifier. Finally, it is connected to an acousto-optic modulator so that the beat frequency signals acquired by the ADC chip have the same initial phase, which can reduce coherent fading noise and improve the system signal-to-noise ratio. This allows the φ-OTDR system to reconstruct vibration signals with high frame rate even in the fading region.

[0028] 2) The novel distributed optical fiber acoustic signal acquisition device and method of the present invention uses carrier signals cos80MHz and sin80MHz, which are in phase and frequency with the high voltage pulse modulation signal, to perform I / Q demodulation on the beat frequency signal, which solves the problem of phase imbalance after I / Q demodulation and makes the acoustic signal restoration more accurate.

[0029] 3) The novel distributed optical fiber acoustic 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, and transmits the vibration signal frame and phase signal frame to the computer through the TCP / IP protocol at the PS end, which reduces the data processing pressure on the computer and improves the time for distributed optical fiber vibration signal capture and reconstruction. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

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

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

[0033] Figure 3 This is a schematic diagram of the internal functional modules of the ZYNQ chip in a novel distributed optical fiber acoustic signal acquisition device according to the present invention.

[0034] Figure 4 This is a structural diagram of an external differential coherent φ-OTDR system applicable to a novel distributed optical fiber acoustic signal acquisition device of the present invention. Detailed Implementation

[0035] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

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

[0037] ADC: Analog-to-Digital Converter, a device that converts analog signals into digital signals. It completes the conversion through two main processes: sampling and quantization. The sampling process involves sampling continuous analog signals at fixed time intervals, while quantization converts the sampled signal values ​​into the closest possible digital values.

[0038] As described in the background section, the purpose of this invention is to overcome the shortcomings of the prior art and provide a novel distributed optical fiber acoustic signal acquisition device and method, which can reduce coherent fading noise, improve the system signal-to-noise ratio, enable the φ-OTDR system to have a high-fidelity vibration signal, and improve the acoustic signal reproduction and distributed optical fiber vibration capture response time.

[0039] Example 1

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

[0041] In a typical embodiment of the present invention, such as Figure 1 As shown, this embodiment discloses a novel distributed fiber optic acoustic signal acquisition device applied to a heterodyne coherent detection φ-OTDR system, comprising: 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 (PL terminal), and a processing system terminal (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 RF device and the power amplifier to output a high-voltage pulse modulation signal; the clock module includes a clock synchronizer and a crystal oscillator, which are driven by the control module to generate two clock signals, a first clock signal and a second clock signal, which are in phase but have different frequencies; the first clock signal is input to the PWM module and the mixer, respectively, and the second clock signal is input to the ADC acquisition module and the ADC processor, respectively.

[0042] In this embodiment, the control module uses a ZYNQ chip, the ADC processor uses an ADC chip, and the crystal oscillator uses an 80MHz crystal oscillator as the clock source for 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 terminal of the control module drives a clock synchronizer via an SPI bus to output two in-phase 80MHz clock signals and two 240MHz clock signals. One of the 80MHz clock signals drives the PWM module to generate a trigger pulse signal input to the mixer, while the other 80MHz clock signal is input to the mixer. Together with the trigger pulse signal, they generate a low-voltage pulse modulation signal. This low-voltage pulse modulation signal is then amplified by a power amplifier to output a high-voltage pulse modulation signal to the acousto-optic modulator. One of the 240MHz clock signals drives the ADC chip to acquire the beat frequency signal, while the other 240MHz clock signal drives the ADC acquisition module to acquire 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 module and a data parsing module, while the PS end includes a signal framing module and a TCP / IP data processing module. Data is transmitted between the PL end and the PS end via an AXI bus. The I / Q demodulation module demodulates the ADC data to obtain I and Q channels. The data parsing module performs vibration data parsing and phase data parsing to obtain vibration data and phase data respectively. The vibration data and phase data are then transmitted via the AXI bus to the signal framing module on the PS end for vibration signal framing and phase signal framing to obtain vibration signal frames and phase signal frames respectively. Finally, the data is transmitted to the computer via the TCP / IP data processing module.

[0045] Specifically, the I / Q demodulation module includes a DDS module. The DDS module uses a first clock signal (80MHz) 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 module. The cos80MHz and sin80MHz signals are multiplied by the ADC data in a multiplier, and then filtered in an FIR low-pass filter to obtain the I and Q data, respectively. The data analysis module includes a vibration data analysis module and a phase data analysis module. In the vibration data analysis module, the amplitude of the I and Q data is calculated to obtain the vibration signal. The vibration signal is then processed sequentially using bandpass filtering, a first moving average, a moving differential, and a second moving average to obtain the vibration data. In the phase data analysis module, the arctangent of the I and Q data is calculated to obtain the phase signal. The phase signal is then processed sequentially using range expansion, initial phase elimination, spatial dewinding, temporal dewinding, DC removal, and moving average to obtain the phase data.

[0046] The signal framing module on the PS side includes a vibration signal framing module and a phase signal framing module. Vibration data is transmitted from the PL side to the signal framing module on the PS side via the AXI bus, where vibration signal frames are generated and transmitted to the computer via the TCP / IP protocol in the TCP / IP data processing module. Similarly, phase data is transmitted from the PL side to the signal framing module on the PS side via the AXI bus, where phase signal frames are generated and transmitted to the computer via the TCP / IP protocol in the TCP / IP data processing module.

[0047] In this embodiment, the ZYNQ control module chip also communicates with the storage module and the gigabit Ethernet port. The storage module includes an SD card and a DDR3 memory for storing programs and data. The gigabit Ethernet port uses a gigabit PHY chip, ensuring correct and high-speed communication between the ZYNQ chip and the computer. Furthermore, the gigabit Ethernet communication in this acquisition device offers greater flexibility, allowing for easy connection to laptops or tablets with lower performance requirements. This overcomes the limitation of existing technologies using PCI-E bus connections, which restrict connection to desktop computers and impose higher performance demands on the host computer.

[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 transmits the configuration parameters to the configuration parameter frame module on the PS end for parsing and processing via the TCP / IP protocol of the TCP / IP data processing module, obtaining five configuration parameters: laser sweep frequency, PWM pulse width, fiber length, data sampling depth, and vibration point information. The PS end transmits the obtained configuration parameters to the configuration parameter processing module on the PL end via the AXI bus. The PL end determines the period and frequency of the PWM pulse signal output by the PWM module using the laser sweep frequency and PWM pulse width parameters, determines the number of ADC data samples acquired by the ADC acquisition module each time using the fiber length and data sampling depth, and determines the corresponding phase data extracted by the phase data parsing module using the vibration point position.

[0049] Example 2

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

[0051] Step 1: The PL terminal of the ZYNQ chip in the control module drives the clock synchronizer through the SPI bus, and outputs two 80MHz clock signals and two 240MHz clock signals in phase respectively.

[0052] Step 2: The PL terminal of the ZYNQ chip in 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 fed into the mixer to generate a low-voltage pulse modulation signal, which is then output as a high-voltage pulse modulation signal through the power amplifier;

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

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

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

[0057] Step 7: The PL terminal of the ZYNQ chip in 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 signals are multiplied with the acquired ADC data in the multiplier, and then filtered in the FIR low-pass filter to obtain the I data and Q data.

[0058] Step 8: Calculate the amplitude of the I and Q data, demodulate the vibration signal, and analyze the vibration signal to obtain the vibration data; specifically: the vibration data analysis module performs a sum of squares and then a square root calculation on the I and Q data to obtain the vibration signal, and then performs bandpass filtering, first moving average, moving difference and second moving average processing on the vibration signal to obtain the vibration data.

[0059] Step 9: Calculate the arctangent of the I and Q data to extract the phase signal, and analyze the phase signal to obtain the phase data; specifically, the phase data analysis module performs arctangent calculation on the I and Q data to obtain the phase signal, and sequentially performs value range expansion, initial phase elimination, spatial unwinding, temporal unwinding, DC removal, and moving 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 via the AXI bus. The vibration signal framing module on the PS end performs vibration signal framing processing to obtain vibration signal frames, which are then transmitted to the computer via 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 via the AXI bus. The phase signal framing module on the PS end performs phase signal framing processing to obtain phase signal frames, which are then transmitted to the computer via the TCP / IP protocol of the TCP / IP data processing module.

[0062] The computer transmits configuration parameters to the configuration parameter frame module on the PS side of the ZYNQ chip via TCP / IP protocol for parsing and processing, obtaining five configuration parameters: laser sweep frequency, PWM pulse width, fiber length, data sampling depth, and vibration point information. The PS side then transmits these configuration parameters to the configuration parameter processing module on the PL side of the ZYNQ chip via the AXI bus. The PL side uses the laser sweep frequency and PWM pulse width parameters to determine the period and frequency of the PWM pulse signal output by the PWM module, uses the fiber length and data sampling depth to determine the number of ADC data points collected by the ADC acquisition module each time, and uses the vibration point position to determine the phase data extracted by the phase data parsing module.

[0063] This invention provides a novel distributed fiber optic acoustic signal acquisition device and method. It uses an 80MHz clock signal to generate a trigger pulse signal, which is then fed into a mixer along with the 80MHz clock signal. The result is then amplified by a power amplifier to output a high-voltage pulse modulation signal, which is finally connected to an acousto-optic modulator. This ensures that the beat frequency signals acquired by the ADC processor all have the same initial phase, reducing coherent fading noise and improving the system's signal-to-noise ratio. This allows the φ-OTDR system to reconstruct high-fidelity vibration signals even in fading regions. Furthermore, by using a carrier signal cos80MHz that is in phase and frequency with the high-voltage pulse modulation signal... The sin80MHz frequency signal is used for I / Q demodulation, which solves the problem of unclear phase signal demodulation and poor sensitivity caused by phase imbalance after I / Q demodulation, resulting in higher sound wave signal restoration. The I / Q demodulation, vibration signal analysis and phase signal analysis processing are realized through the PL terminal of the ZYNQ chip control module. The vibration signal frame and phase signal frame are transmitted to the computer via TCP / IP protocol through the PS terminal, which reduces the data processing pressure of the distributed fiber optic acoustic wave detection host, lowers the performance requirements of the detection host, and improves the response time of distributed fiber optic vibration capture, which is conducive to the development of portable distributed fiber optic acoustic wave detection systems.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A novel distributed fiber optic acoustic signal acquisition device, characterized in that, include: Control module, clock module, acousto-optic modulator, ADC processor, mixer, and power amplifier; The control module includes an ADC acquisition module, a PWM module, a programmable logic terminal, and a processing system terminal. The ADC acquisition module receives ADC data transmitted by the ADC processor and is sequentially connected to the programmable logic terminal and the processing system terminal for signal processing. The processing system terminal includes a signal framing module and a TCP / IP data processing module. The programmable logic terminal and the processing system terminal transmit data via an AXI bus. The signal framing module includes a vibration signal framing module and a phase signal framing module. The PWM module is sequentially connected to a radio frequency device and a power amplifier to output a high-voltage pulse modulation signal. The programmable logic terminal includes an I / Q demodulation module and a data parsing module; the I / Q demodulation 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 an FIR low-pass filter to obtain I data and Q data respectively; the data parsing module includes a vibration data parsing module and a phase data parsing module; The clock module includes a clock synchronizer and a crystal oscillator, which are driven by the control module to generate two clock signals with the same phase but different frequencies: a first clock signal and a second clock signal; the first clock signal is input to the PWM module and the mixer, respectively, and the second clock signal is input to the ADC acquisition module and the ADC processor, respectively. A trigger pulse signal is generated using an 80MHz clock signal. The trigger pulse signal and the 80MHz clock signal are fed into a mixer, and then the output is a high-voltage pulse modulation signal through a power amplifier. Finally, it is connected to an acousto-optic modulator, so that the beat frequency signals acquired by the ADC processor all have the same initial phase. By using carrier signals cos80MHz and sin80MHz, which are in phase and frequency with the high-voltage pulse modulation signal, I / Q demodulation of the beat frequency signal is performed, which solves the problem of unclear phase signal demodulation and poor sensitivity caused by phase imbalance after I / Q demodulation.

2. The novel distributed optical fiber acoustic signal acquisition device as described in claim 1, characterized in that, The control module is also connected to the storage module and the gigabit network port for communication.

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

4. A novel distributed optical fiber acoustic signal acquisition method applicable to the novel distributed optical fiber acoustic signal acquisition device as described in claim 1, characterized in that, include: The programmable logic terminal of the control module drives the clock synchronizer to output two first clock signals and two second clock signals that are in phase but have different frequencies. The programmable logic terminal 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 fed into the mixer to generate a low-voltage pulse modulation signal, which is then output as a high-voltage pulse modulation signal by the power amplifier and connected to the acousto-optic modulator. The programmable logic terminal uses a second clock signal to drive the ADC processor to acquire beat frequency signals in real time. The programmable logic terminal uses a second clock signal to drive the ADC acquisition module to acquire ADC data.

5. The novel distributed optical fiber acoustic signal acquisition method as described in claim 4, characterized in that, include: The programmable logic terminal uses the first clock signal to generate the cosine I / Q demodulation carrier signal and the sine I / Q demodulation carrier signal required by the I / Q demodulation function module, respectively; The beat frequency signal is demodulated using cosine I / Q demodulation carrier signal and sine I / Q demodulation carrier signal to obtain I data and Q data; The amplitude of the I and Q data is calculated and demodulated to obtain the vibration signal, and the vibration signal is analyzed to obtain the vibration data. The phase signal is extracted by calculating the arctangent of the I and Q data, and the phase data is obtained by analyzing the phase signal. Vibration data and phase data are transmitted to the processing system via the AXI bus. The processing system then assembles vibration signal frames and phase signal frames and transmits them to the computer via the TCP / IP protocol.

6. The novel distributed optical fiber acoustic signal acquisition method as described in claim 5, characterized in that, The vibration data is obtained by analyzing the vibration signal. Specifically, the programmable logic terminal performs bandpass filtering, first moving average, moving differential and second moving average processing on the demodulated vibration signal to obtain the vibration data.

7. The novel distributed optical fiber acoustic signal acquisition method as described in claim 5, characterized in that, The process of obtaining phase data by analyzing the phase signal involves the following steps: the programmable logic terminal performs range expansion, random initial phase elimination, spatial dewinding, temporal dewinding, DC removal, and moving average processing on the demodulated phase signal to obtain the phase data.

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