Multi-channel photoelectric signal sampling method and distributed optical fiber sensing system

Abstract

The invention relates to a multichannel photoelectric signal sampling method and a distributed optical fiber sensing system. The method is applied to a distributed optical fiber sensing system, the distributed optical fiber sensing system comprises at least two photoelectric signal receiving and transmitting channels and at least two analog-to-digital conversion acquisition channels, and the method comprises the following steps: when photoelectric input signals of the photoelectric signal receiving and transmitting channels meet a preset sampling condition, sampling the photoelectric input signals of the photoelectric signal receiving and transmitting channels; switching the input ends of the at least two analog-to-digital conversion acquisition channels to the photoelectric signal transceiving channel; based on a preset reference clock signal, controlling the analog-to-digital conversion acquisition channel to perform hybrid sampling on the photoelectric input signal to obtain a target sampling signal; the sampling spatial resolution of the mixed sampling is integral multiples of the sampling spatial resolution of the analog-to-digital conversion acquisition channel. By adopting the method, the high-frequency signal sampling precision and flexibility can be improved.

Description

Technical Field

[0001] This application relates to the field of signal acquisition technology, and in particular to a multi-channel photoelectric signal sampling method and a distributed optical fiber sensing system. Background Technology

[0002] With the development of distributed fiber optic sensing technology, multi-channel signal acquisition systems have been widely used in vibration monitoring. However, the sampling rate of the signal in each channel is often limited by the performance of a single analog-to-digital converter (ADC), resulting in insufficient sampling accuracy, low spatial resolution, and high hardware costs for high-frequency vibration signals. Traditional technologies have addressed the problem of insufficient sampling accuracy of high-frequency vibration signals by improving the performance of a single ADC or adding hardware. However, improving performance and adding ADC hardware are costly and cannot be flexibly adapted to various scenarios.

[0003] It is evident that existing technologies still suffer from low sampling accuracy and limited flexibility in high-frequency signals. Summary of the Invention

[0004] Therefore, it is necessary to provide a multi-channel photoelectric signal sampling method and a distributed optical fiber sensing system that can improve the sampling accuracy and flexibility of high-frequency signals, in order to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a multi-channel photoelectric signal sampling method applied to a distributed optical fiber sensing system, the distributed optical fiber sensing system including at least two photoelectric signal transceiver channels and at least two analog-to-digital conversion acquisition channels, the multi-channel photoelectric signal sampling method including:

[0006] When the photoelectric input signal of the photoelectric signal transceiver channel meets the preset sampling conditions, the input terminals of at least two analog-to-digital conversion acquisition channels are switched to the photoelectric signal transceiver channel;

[0007] Based on a preset reference clock signal, the analog-to-digital conversion acquisition channel is controlled to perform mixed sampling on the photoelectric input signal to obtain the target sampling signal; the sampling spatial resolution of the mixed sampling is an integer multiple of the sampling spatial resolution of the analog-to-digital conversion acquisition channel.

[0008] In one embodiment, the preset sampling conditions include channel vibration conditions; the step of switching the input terminals of at least two analog-to-digital conversion acquisition channels to the photoelectric signal transceiver channel when the photoelectric input signal of the photoelectric signal transceiver channel meets the preset sampling conditions includes:

[0009] When the vibration state of the signal in at least one photoelectric signal transceiver channel meets the channel vibration condition, at least two of the analog-to-digital conversion acquisition channels are switched to the photoelectric signal transceiver channel.

[0010] In one embodiment, when there are multiple photoelectric signal transceiver channels that meet preset sampling conditions, switching at least two of the analog-to-digital conversion acquisition channels to the photoelectric signal transceiver channels includes:

[0011] Record the channel number of each photoelectric signal transceiver channel that meets the preset sampling conditions in sequence;

[0012] Based on the channel number, the input terminals of at least two of the analog-to-digital conversion acquisition channels are sequentially switched to the photoelectric signal transceiver channel corresponding to the channel number.

[0013] In one embodiment, controlling the analog-to-digital conversion acquisition channel to perform mixed sampling of the photoelectric input signal based on a preset reference clock signal to obtain the target sampled signal includes:

[0014] The preset reference clock signal is divided by frequency to obtain at least two frequency-divided clock signals with different timing sequences; the number of frequency-divided clock signals is the same as the number of analog-to-digital conversion acquisition channels.

[0015] Based on the frequency division clock signal, the analog-to-digital conversion acquisition channel is controlled to sample the photoelectric input signal to obtain a timing sampling signal;

[0016] The target sampling signal is determined based on multiple timing sampling signals.

[0017] In one embodiment, the frequency of the preset reference clock signal is the product of the sampling rate and the number of the analog-to-digital conversion acquisition channels; the step of dividing the preset reference clock signal to obtain at least two frequency-divided clock signals with different timings includes:

[0018] Based on the period of the preset reference clock signal, the start time of each analog-to-digital conversion acquisition channel is determined sequentially;

[0019] Based on the reference clock signal and the start time, at least two frequency-divided clock signals are generated.

[0020] In one embodiment, the step of controlling the analog-to-digital conversion acquisition channel to perform mixed sampling of the photoelectric input signal based on a preset reference clock signal to obtain the target sampled signal includes:

[0021] After a preset waiting time, the input terminal of the analog-to-digital conversion acquisition channel is switched sequentially to the preset photoelectric signal transceiver channel corresponding to the analog-to-digital conversion acquisition channel.

[0022] Secondly, this application provides a distributed optical fiber sensing system, which includes a signal detection module, a channel switching module, and a sampling control module; wherein:

[0023] The signal detection module includes at least two photoelectric signal transceiver channels;

[0024] The sampling control module includes a control unit and at least two analog-to-digital conversion acquisition channels; the at least two analog-to-digital conversion acquisition channels are connected to the at least two photoelectric signal transceiver channels through the channel switching module; the control unit is used to execute the multi-channel photoelectric signal sampling method described above.

[0025] In one embodiment, the photoelectric signal transceiver channel includes a light source unit, an optical modulation and amplification unit, an optical signal receiving unit, a photoelectric signal conversion unit, and an optical fiber unit;

[0026] The light source unit is used to generate and emit light signals;

[0027] The optical modulation and amplification unit is used to modulate and amplify the optical signal to obtain an amplified optical signal;

[0028] The photoelectric signal conversion unit acquires the amplified optical signal sequentially through the optical signal receiving unit and the optical fiber unit; converts the optical signal into a photoelectric input signal; and sends the photoelectric input signal to the sampling control module through the channel switching module.

[0029] In one embodiment, the sampling control module further includes a pulse shaping unit, and the control unit is further configured to send a pulse signal to the optical modulation and amplification unit through the pulse shaping unit; the pulse shaping unit is further configured to shape the pulse signal to generate a pulse driving signal; and the optical modulation and amplification unit is configured to modulate and amplify the optical signal based on the pulse driving signal.

[0030] In one embodiment, the channel switching module includes at least two channel switching units; the input terminal of each channel switching unit is connected to at least two of the photoelectric signal transceiver channels; and the output terminal of each channel switching unit is connected to the input terminal of one of the analog-to-digital conversion acquisition channels.

[0031] The channel switching unit is also connected to the control unit and is used to turn on or off based on the channel switching command of the control unit.

[0032] The aforementioned multi-channel photoelectric signal sampling method and distributed optical fiber sensing system, by switching the input terminals of at least two analog-to-digital conversion acquisition channels to the photoelectric signal transceiver channel when the photoelectric input signal of the photoelectric signal transceiver channel meets the preset sampling conditions; and controlling the analog-to-digital conversion acquisition channel to perform mixed sampling of the photoelectric input signal based on a preset reference clock signal to obtain the target sampled signal; the sampling spatial resolution of the mixed sampling is an integer multiple of the sampling spatial resolution of the analog-to-digital conversion acquisition channel. By dynamically switching the analog-to-digital conversion acquisition channel when the photoelectric input signal meets the preset conditions, the system can improve the equivalent sampling rate of signal sampling and suppress quantization noise while achieving flexible resource allocation without adding an analog-to-digital converter at a low cost, thereby achieving the technical effect of improving the sampling accuracy and flexibility of high-frequency signals. Attached Figure Description

[0033] Figure 1 This is a block diagram of a distributed fiber optic sensing system in one embodiment;

[0034] Figure 2 This is a flowchart illustrating a multi-channel photoelectric signal sampling method in one embodiment;

[0035] Figure 3 This is a flowchart illustrating a multi-channel photoelectric signal sampling method in another embodiment;

[0036] Figure 4 This is a schematic diagram of the timing allocation of four ADC channels in one embodiment;

[0037] Figure 5 This is a schematic diagram illustrating the allocation of channel connections in one embodiment;

[0038] Figure 6 This is a block diagram of a distributed fiber optic sensing system in another embodiment;

[0039] Figure 7 This is a schematic diagram illustrating the timing allocation of the reference clock and the sampling clock in one embodiment. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0041] The multi-channel photoelectric signal sampling method provided in this application is applied to a distributed optical fiber sensing system, which includes at least two photoelectric signal transceiver channels and at least two analog-to-digital conversion acquisition channels. For example, the multi-channel photoelectric signal sampling method provided in this application can be applied to systems such as... Figure 1 In the application environment shown, the distributed optical fiber sensing system includes a signal detection module 100, a channel switching module 200, and a sampling control module 300. The signal detection module 100 includes at least two photoelectric signal transceiver channels; the sampling control module 200 includes at least two analog-to-digital conversion (ADC) acquisition channels; the at least two ADC acquisition channels are connected to the at least two photoelectric signal transceiver channels through the channel switching module 200; the sampling control module 300 is used to switch the input terminals of the at least two ADC acquisition channels to the photoelectric signal transceiver channels when the photoelectric input signal of the photoelectric signal transceiver channel meets the preset sampling conditions; and based on a preset reference clock signal, it controls the ADC acquisition channels to perform mixed sampling of the photoelectric input signal to obtain the target sampling signal.

[0042] In one embodiment, such as Figure 2 As shown, a multi-channel photoelectric signal sampling method is provided, which can be applied to applications such as... Figure 1 Taking the distributed fiber optic sensing system shown as an example, the multi-channel photoelectric signal sampling method includes:

[0043] Step S100: When the photoelectric input signal of the photoelectric signal transceiver channel meets the preset sampling conditions, the input terminals of at least two analog-to-digital conversion acquisition channels are switched to the photoelectric signal transceiver channel.

[0044] Among them, the distributed optical fiber sensing system can be a sensing system that uses the optical fiber itself as a sensing medium and signal transmission channel. By injecting laser pulses into the optical fiber, the backscattered light signals generated by the interaction between the light and the optical fiber material during the propagation process are analyzed using optical time-domain reflectometry, such as Rayleigh scattering and Raman scattering. This enables continuous, real-time, and high-precision monitoring of physical quantities such as temperature, strain, vibration, and sound waves along the optical fiber.

[0045] A photoelectric signal transceiver channel can be a physical path for receiving and transmitting photoelectric input signals, or it can be a material signal transceiver achieved by connecting a sensor and an analog-to-digital converter.

[0046] The preset sampling conditions can be pre-set trigger thresholds. For example, they can include judgment criteria such as the signal frequency exceeding a specific threshold, the amplitude reaching a preset value, or the appearance of a specific waveform. In an exemplary embodiment, the preset sampling conditions can be used to determine whether the photoelectric input signal of the photoelectric signal transceiver channel is a high-frequency vibration signal, thereby determining whether the photoelectric input signal is a signal that needs to be processed by the multi-channel photoelectric signal sampling method of this embodiment.

[0047] The analog-to-digital conversion (ADC) acquisition channel can be a signal acquisition channel including an ADC, used to acquire analog signals and convert them into digital signals. In this embodiment, the number of ADC acquisition channels and photoelectric signal transceiver channels can be the same. Initially, each ADC acquisition channel can be connected to one photoelectric signal transceiver channel. If sampling is not performed on each photoelectric signal transceiver channel at any given time, the number of ADC acquisition channels can also be less than the number of photoelectric signal transceiver channels. The ADC acquisition channel is switched to the target photoelectric signal transceiver channel only when the number of photoelectric signal transceiver channels meets a preset sampling condition.

[0048] Switching the input terminals of at least two analog-to-digital (ADC) acquisition channels to the optoelectronic signal transceiver channel can be achieved through dynamic signal path adjustment using electronic devices such as electronic switch matrices or multiplexers. For example, after the control module sends a switching command to the multiplexer, an electrical connection is established between the input ports of multiple ADC acquisition channels and the target optoelectronic signal transceiver channel. Furthermore, the number of ADC acquisition channels switched to the optoelectronic signal transceiver channel can be less than or equal to the total number of ADC acquisition channels. For instance, the number of ADC acquisition channels matching the signal characteristics of the optoelectronic input signal can be determined based on the signal characteristics, and the corresponding number of available ADC acquisition channels can be switched to the optoelectronic signal transceiver channel.

[0049] For example, a multiplexing signal can be sent to the multiplexer via the control module to control the switching of the analog-to-digital converter (ADC) acquisition channels. In some exemplary embodiments, control commands can be transmitted via I²C bus, GPIO interface, etc., thereby dynamically adjusting the connection relationship between the signal transmission and reception paths and the ADC acquisition channels. This allows for dynamic allocation of hardware resources for collaborative sampling of multiple ADCs without adding ADCs, achieving low cost.

[0050] Step S200: Based on a preset reference clock signal, control the analog-to-digital conversion acquisition channel to perform mixed sampling of the photoelectric input signal to obtain the target sampling signal.

[0051] The preset reference clock signal is a high-stability timing reference generated by a clock generator. For example, it can be generated using a temperature-compensated crystal oscillator, a constant-temperature crystal oscillator, or other clock sources.

[0052] Hybrid sampling can be achieved by alternating or interleaving sampling through multiple analog-to-digital converter (ADC) acquisition channels to improve the equivalent sampling rate. For example, undersampling techniques can be used to sample high-frequency signals using a clock signal higher than the Nyquist frequency, while oversampling techniques can be used to reduce quantization noise by increasing the sampling frequency. In this embodiment, a preset reference clock signal can be divided into phase-shifted sub-clock signals to generate sampling pulses of different phases, which are then sent to the sampling trigger terminals of each ADC acquisition channel. Furthermore, the sampling spatial resolution of hybrid sampling is an integer multiple of the sampling spatial resolution of the ADC acquisition channel. In an exemplary embodiment, hybrid sampling can be achieved by using multiple ADC channels to alternately sample the photoelectric input signal of the same photoelectric input signal channel based on a preset reference clock signal, such that the sampling spatial resolution of hybrid sampling can be the resolution of the preset reference clock signal, or the product of the resolution of the ADC acquisition channel and the number of channels.

[0053] In an exemplary embodiment, a preset reference clock signal can be processed by a frequency divider circuit to generate a phase-shifted sub-clock sequence, which includes multiple sub-clock signals with different phases. Each analog-to-digital conversion acquisition channel synchronously starts sampling based on the received sub-clock signals. The sampled data can be reassembled according to timestamps, for example, by sorting data packets using a FIFO buffer or programmable logic device. By superimposing multiple analog-to-digital conversion acquisition channels in the time dimension, an equivalent sampling rate several times that of a single analog-to-digital conversion acquisition channel can be achieved.

[0054] This embodiment provides a multi-channel photoelectric signal sampling method. When the photoelectric input signal of the photoelectric signal transceiver channel meets a preset sampling condition, the input terminals of at least two analog-to-digital conversion (ADC) acquisition channels are switched to the photoelectric signal transceiver channel. Based on a preset reference clock signal, the ADC acquisition channels are controlled to perform mixed sampling of the photoelectric input signal to obtain a target sampled signal. The sampling spatial resolution of the mixed sampling is an integer multiple of the sampling spatial resolution of the ADC acquisition channel. By dynamically switching the ADC acquisition channel when the photoelectric input signal meets the preset condition, the method can improve the equivalent sampling rate of the signal sampling and suppress quantization noise while achieving flexible resource allocation without adding an ADC at a low cost. This achieves the technical effect of improving the sampling accuracy and flexibility of high-frequency signals.

[0055] In one embodiment, the preset sampling conditions include channel vibration conditions; when the photoelectric input signal of the photoelectric signal transceiver channel meets the preset sampling conditions, switching the input terminals of at least two analog-to-digital conversion acquisition channels to the photoelectric signal transceiver channel includes:

[0056] When the vibration state of the signal in at least one photoelectric signal transceiver channel meets the channel vibration condition, at least two analog-to-digital conversion acquisition channels are switched to the photoelectric signal transceiver channel.

[0057] The channel vibration conditions can be used to determine whether the vibration state of the vibration signal meets the conditions requiring collaborative sampling by multiple analog-to-digital conversion acquisition channels. For example, channel vibration conditions may include vibration frequency exceeding a threshold, sudden changes in vibration amplitude, vibration duration exceeding a preset duration, and specific vibration modes. Furthermore, the threshold for vibration frequency and amplitude can be determined statistically based on historical signals of the photoelectric input signal, identifying thresholds that distinguish between normal and target conditions. The preset duration can be based on statistical analysis of historical vibration durations, including the highest duration of occasional high-frequency vibrations, the lowest duration of continuous high-frequency vibrations, or calculations based on averages, medians, etc. Specific vibration modes may include impact vibrations. The acquisition or generation methods for channel vibration conditions can be configured according to the actual application scenario; for example, in earthquake monitoring, high-frequency vibrations may be emphasized, while in mechanical fault diagnosis, specific frequency bands may be considered.

[0058] Vibration state can be a set of physical properties of the photoelectric input signal acquired in real time by the photoelectric signal transceiver channel, which may include one or more dynamic parameters such as vibration frequency, amplitude, waveform morphology, and phase change. For example, vibration state can be obtained through a signal preprocessing module. For instance, the vibration state of the photoelectric input signal can be obtained through techniques such as bandpass filtering to extract the target frequency band, peak detection to calculate the amplitude, and Fourier transform analysis of spectral characteristics.

[0059] In this embodiment, the switching of the analog-to-digital conversion acquisition channel is determined by the vibration state meeting the channel vibration conditions. This can be achieved by performing real-time analysis of the photoelectric input signal, matching the extracted parameters with the channel vibration conditions, and triggering the switching of the analog-to-digital conversion acquisition channel when a successful match is found. This activates the resources of multiple analog-to-digital conversion acquisition channels only when high-precision sampling is required, rather than continuously occupying hardware resources, thereby improving energy efficiency.

[0060] This embodiment provides a multi-channel photoelectric signal sampling method that uses channel vibration conditions as the sampling trigger and analyzes the characteristic parameters of the vibration state to achieve intelligent resource allocation. This enables the technical effects of accurately identifying vibration signals in complex dynamic environments, dynamically optimizing sampling resource configuration, and improving system utilization.

[0061] In one embodiment, when there are multiple photoelectric signal transceiver channels that meet preset sampling conditions, switching at least two analog-to-digital conversion acquisition channels to photoelectric signal transceiver channels includes:

[0062] Record the channel number of each photoelectric signal transceiver channel that meets the preset sampling conditions in sequence;

[0063] Based on the channel number, the input terminals of at least two analog-to-digital conversion acquisition channels are sequentially switched to the photoelectric signal transceiver channel corresponding to the channel number.

[0064] The channel number can be a unique identifier assigned to each photoelectric signal transceiver channel, used to establish the mapping relationship between the photoelectric input signal path and hardware resources. For example, it can be implemented through a hardware address bus or a software configuration table. Furthermore, the channel number can be a binary-encoded channel number or a sequential number based on spatial location. Further, the channel number information can be stored in a data cache module or register group, with matching channel numbers stored in a first-in-first-out queue or static array according to the trigger order. Sequential switching can be achieved by sequentially reading the stored channel numbers and generating a corresponding channel switching signal based on the read channel number to control channel switching.

[0065] This embodiment provides a multi-channel photoelectric signal sampling method. By sequentially recording the channel numbers of photoelectric signal transceiver channels that meet the conditions and establishing an ordered sequence, the analog-to-digital conversion acquisition channel is switched to the target photoelectric signal transceiver channel based on this sequence. This can solve the resource contention problem when multiple target channels are triggered simultaneously, improve the execution determinism of the collaborative work of multiple analog-to-digital conversion acquisition channels and multiple photoelectric signal transceiver channels, and achieve the technical effect of improving system reliability and stability.

[0066] In one embodiment, based on a preset reference clock signal, the analog-to-digital conversion acquisition channel is controlled to perform mixed sampling of the photoelectric input signal to obtain the target sampled signal, including:

[0067] The preset reference clock signal is divided to obtain at least two frequency-divided clock signals with different timing sequences; the number of frequency-divided clock signals is the same as the number of analog-to-digital conversion acquisition channels.

[0068] Based on the frequency division clock signal, the analog-to-digital conversion acquisition channel is controlled to sample the photoelectric input signal to obtain the timing sampling signal;

[0069] The target sampling signal is determined based on multiple time-series sampling signals.

[0070] Frequency division processing involves using a clock divider to reduce the reference clock frequency to the target frequency, thereby generating a frequency-divided clock signal sequence with a preset phase offset. The divider can be a digital logic circuit, a dedicated clock chip, etc., and its output frequency-divided clock signal must satisfy the characteristic of uniform phase distribution. For example, if the system includes two analog-to-digital converter (ADC) acquisition channels, the divider can equally divide the reference clock frequency into two clock signals with a phase difference of 180°; if it includes four ADC acquisition channels, the phase difference can be 90°. The number of frequency-divided clock signals can be the same as the number of ADC acquisition channels, thus forming a time-interleaved sampling sequence.

[0071] Based on a frequency-division clock signal, the analog-to-digital converter (ADC) acquisition channels sample the photoelectric input signal to obtain a timing sampling signal. This can be achieved by sending corresponding frequency-division clock signals to each ADC acquisition channel and coordinating their sampling trigger timing. Furthermore, the ADC acquisition channels can trigger a sample-and-hold circuit based on the rising or falling edge of the received clock signal to capture the instantaneous voltage value of the photoelectric input signal. After sampling, the ADC acquisition channels convert the analog signal into a digital quantity and store multiple digital quantities as a timing sampling signal.

[0072] Determining the target sampling signal based on multiple timing sampling signals can be achieved by recombining and correcting the timing sampling signals output from each analog-to-digital converter acquisition channel. For example, the sampling data from each analog-to-digital converter acquisition channel can be arranged in chronological order based on the phase offset parameter of the frequency divider clock.

[0073] Furthermore, interpolation algorithms, such as linear interpolation or spline interpolation, can be used to fill in the tiny time gaps caused by clock division.

[0074] Correcting the timing sampling signals output by each analog-to-digital conversion acquisition channel can correct phase deviations caused by inherent delay differences between analog-to-digital conversion acquisition channels. For example, this can be done by using pre-calibrated and stored delay compensation values, and then merging the ordered and corrected sampling point sequence into a high-resolution target sampling signal.

[0075] This embodiment provides a multi-channel photoelectric signal sampling method. By precisely controlling the phase of the frequency-division clock signal, it can ensure that the sampling of multiple analog-to-digital conversion acquisition channels follows the time-interlacing rule of the frequency division, so that the equivalent sampling rate increases linearly with the number of analog-to-digital conversion acquisition channels, while avoiding the spectral aliasing problem in traditional technologies. The correspondence between the number of frequency-division clocks and the number of analog-to-digital conversion acquisition channels allows the system to flexibly adapt to different hardware configurations, and can improve the sampling rate on the basis of the original number of analog-to-digital conversion acquisition channels, thereby improving the sampling resolution and anti-interference capability of high-frequency vibration signals.

[0076] In one embodiment, the preset reference clock signal is divided to obtain at least two frequency-divided clock signals with different timings, including:

[0077] Based on the period of the preset reference clock signal, the start time of each analog-to-digital conversion acquisition channel is determined sequentially;

[0078] Based on the reference clock signal and the start time, at least two frequency-divided clock signals are generated.

[0079] The frequency of the preset reference clock signal is the product of the sampling rate and the number of analog-to-digital converter (ADC) acquisition channels. For example, when the sampling rate of a single ADC acquisition channel is 10 MS / s and the system has four channels, the reference clock frequency can be set to 40 MHz. By adjusting the sampling rate and number of ADC acquisition channels, the period of the reference clock signal can be evenly divided into phase intervals corresponding to the number of channels. For instance, in a four-channel system, each period can be divided into four phase segments, thus allocating an independent sampling time window for each channel.

[0080] The start time of the analog-to-digital conversion (ADC) acquisition channels can be the time point at which each ADC acquisition channel begins its first sampling, and its distribution satisfies the condition of uniformly covering the period of the reference clock signal. For example, in a two-channel system, the start time can be set to 0 and T / 2 (where T is the period of the reference clock signal); in a four-channel system, it can be set to 0, T / 4, T / 2, or 3T / 4. The start time can be achieved by reading the edge trigger signal of the reference clock through a timing controller and combining it with delay parameters, such as using a delay-locked loop (PLL) module in an FPGA to dynamically calculate the delay time of each channel.

[0081] The frequency-divided clock signal can be a clock pulse sequence that has undergone frequency adjustment and phase shift processing. For example, after processing the reference clock signal by a frequency divider, a frequency corresponding to the number of channels can be obtained. For instance, a 40MHz reference clock signal, after being divided by 4, has a frequency of 10MHz. Simultaneously, a preset phase shift is added to the clock signal of each channel through a delay unit or a digital phase controller. In an exemplary embodiment, the four frequency-divided clock signals of the four-channel system correspond to phase shifts of 0°, 90°, 180°, and 270°, respectively, ensuring that the sampling points are evenly distributed within the signal period.

[0082] This embodiment provides a multi-channel photoelectric signal sampling method. The ratio constraint between the reference clock and channel parameters avoids the problem of uneven sampling intervals caused by clock frequency mismatch. By uniformly distributing the start time, the spectral leakage phenomenon in high-frequency signal sampling can be reduced. Through timing control, the calibration complexity can be reduced, the equivalent sampling rate can be improved, and the technical effect of improving the sampling accuracy and flexibility of high-frequency signals can be achieved.

[0083] In one embodiment, based on a preset reference clock signal, the analog-to-digital conversion acquisition channel is controlled to perform mixed sampling of the photoelectric input signal to obtain the target sampled signal, which then includes:

[0084] After a preset waiting time, the input terminals of the analog-to-digital conversion acquisition channels are switched sequentially to the preset photoelectric signal transceiver channels corresponding to the analog-to-digital conversion acquisition channels.

[0085] The preset waiting time can be a fixed time interval predefined by the system based on hardware processing latency or data transmission timing. Its value can be determined by one or more parameters such as the completion time of data output from the analog-to-digital conversion acquisition channel, the data buffer write time, and an integer multiple of the system clock cycle. For example, the preset waiting time can include a value that is an integer multiple of the sum of the analog-to-digital conversion acquisition channel's conversion time and the data transmission delay. In an exemplary embodiment, when the analog-to-digital conversion acquisition channel takes 10 microseconds to convert and the data transmission takes 5 microseconds, it can be set to a range of 15 to 20 microseconds.

[0086] The preset photoelectric signal transceiver channel can be the signal transceiver path that the analog-to-digital conversion acquisition channel is connected to by default in the initial state. For example, the preset photoelectric signal transceiver channel can include channels with specific numbers in the fiber optic sensor array, such as the first analog-to-digital conversion acquisition channel being connected to the third channel of the fiber optic sensor by default, the second analog-to-digital conversion acquisition channel being connected to the fifth channel, and so on, with a fixed mapping relationship.

[0087] Sequential switching can be performed in an orderly manner by controlling the connection status of the control signal path, or it can be executed in the order of channel numbers, for example, updating the control signals sequentially from channel 1 to channel N.

[0088] For example, after the mixed sampling phase ends, the current status of the analog-to-digital conversion (ADC) acquisition channels can be monitored. Once it is confirmed that all ADC acquisition channels have completed data output and the buffers have been cleared, a wait timer is started to count down. After the waiting time expires, the default photoelectric signal transceiver channel identifier corresponding to each ADC acquisition channel is read from the preset channel mapping table, and a corresponding channel switching signal is generated. The channel switching signals are sent sequentially to the control terminal of the ADC acquisition channels in a preset order, causing the input port of each ADC acquisition channel to disconnect from the currently connected photoelectric signal transceiver channel and reconnect to the initially configured preset photoelectric signal transceiver channel. This ensures that each ADC acquisition channel regains its independent working capability after releasing shared resources, avoiding data loss due to timing conflicts during switching. Simultaneously, it maintains a dynamic balance between high-frequency sampling and conventional monitoring modes in the distributed fiber optic sensing system, improving hardware resource utilization.

[0089] This embodiment provides a multi-channel photoelectric signal sampling method that, by precisely controlling the waiting time, ensures data integrity while avoiding system response delay. The restoration mechanism connecting the channel to the preset photoelectric signal transceiver channel enables multiple analog-to-digital conversion acquisition channels to quickly return to the normal monitoring mode after working together, avoiding long-term idle hardware resources, thereby achieving the technical effect of improving the flexibility of high-frequency signals.

[0090] To more clearly illustrate the technical solution of this application, a detailed embodiment is also provided.

[0091] In one embodiment, a multi-channel photoelectric signal sampling method is provided, applied to a distributed fiber optic sensing system, such as... Figure 1 As shown, the distributed fiber optic sensing system includes:

[0092] Signal detection module 100 includes a laser emission system (laser source, optical amplification, beam splitting, etc.), N (the number of fiber optic detection channels is denoted as an integer N, N≥2) optical receiving and photoelectric conversion devices, optical fiber, information communication, circuit control, and other components. The detection and acquisition channel number is denoted as M (channel number is an integer M, N≥M≥1). At system startup, if... Figure 3 As shown, upon power-up, the signal detection module 100 first performs a self-test to ensure its internal components are functioning correctly, then enters a standby state. It waits to receive start / stop control information from the sampling control module 300. Upon receiving start / stop information from the sampling control module 300, each optical transceiver channel in the signal detection module 100 begins operation, with the light source sending laser pulse signals to the detection fiber of each channel. During propagation within the detection fiber, the laser pulse signal generates a reverse Rayleigh scattering signal. This reverse Rayleigh scattering signal is converted into an electrical signal S (frequency f) by the photodetector of the corresponding optical transceiver channel within the signal detection module 100. The electrical signals S from all channels are then input to the sampling control module 300 for acquisition. When the sampling control module 300 sends a control signal to shut down the signal detection module 100, all optical transceiver channels of the signal detection module 100 cease operation.

[0093] The sampling control module 300 includes N ADC acquisition channels, i.e., analog-to-digital conversion acquisition channels. In this embodiment, the number of ADC signal acquisition channels is equal to the number of fiber optic detection channels. The ADC acquisition channel number is denoted as M (ADC channel number corresponds to the detection channel), the upper limit sampling rate of each acquisition channel is denoted as F, the period is denoted as T, and it consists of ADC acquisition timing generation circuits, acquisition channel switching control, acquisition data processing, and other functional modules. The signal output from each photoelectric signal channel of the signal detection module 100 is connected to the corresponding numbered ADC data sampling channel. The working process of the sampling control module 300 includes:

[0094] The sampling control module 300 sends a start command to the signal detection module 100, and N fiber optic detection channels begin working to detect vibration and sound signals from the outside world. When a channel detects a vibration signal, it determines whether all channels are vibrating. If all channels are vibrating simultaneously, the system continues to collect signals as before. If not all channels are vibrating, the channel number of the vibrating channel is recorded first, and then, based on the sequence number, the channel with the smaller sequence number is selected for ADC mixed sampling operation. The sequence number of the channel currently undergoing mixed sampling operation is denoted as Ms.

[0095] like Figure 4 As shown, the system controls the ADC acquisition timing through settings and sends input signals to the channel switching module 200 to switch the acquisition channel, loading the sampling capability of other ADC channels onto channel Ms. At this time, the sampling rate of channel Ms is increased to F×N, and the signal acquisition accuracy is restored to a greater extent. Simultaneously, the sampling period is shortened from the original 1 / F to 1 / (F×N). Since the speed of light in an optical fiber is a fixed value, denoted as s, the spatial resolution of the system is shortened from the original (1 / F)×s to (1 / F×N)×s, achieving a sampling spatial resolution increase of N times. The ADC mixed sampling operation hold time T... hold Then the process ends. Next, ADC mixed sampling is performed sequentially on the other channels that detected vibration, until all vibrating channels have completed the ADC mixed sampling operation. Afterward, the system switches the channel switching module 200 to its default state and performs photoelectric data acquisition and analysis on each channel.

[0096] The ADC acquisition timing can be controlled by an acquisition timing control circuit. This circuit staggers the start times of the N ADC acquisition clocks, ensuring that the start times of the N ADC acquisitions are evenly distributed within the ADC acquisition period T. Therefore, the staggered time is T / N. For example, acquisition begins at time 0 with the ADC of channel number 1. After the first T / N time, the ADC of channel number 2 begins acquisition, after the second T / N time, the ADC of channel number 3 begins acquisition, and after the (N-1)th T / N time, the ADC of channel number N begins acquisition. To obtain the T / N time, the frequency of the high-speed reference clock signal is denoted as fb, and the period is denoted as Tb. The frequency fb is the sum of the sampling rates of all acquisition channels' ADCs. That is, fb = N × F, corresponding to the period Tb = T / N. To ensure time alignment, the sampling clocks of the N ADC acquisition channels are uniformly obtained by dividing the high-speed reference clock. At time zero, the ADC sampling clock for channel number 1 is output. After Tb clock cycles, the ADC sampling clock for channel number 2 is output, and so on. After (N-1)Tb clock cycles, the ADC sampling clock for channel number N is output. Figure 5 This is a schematic diagram showing the timing allocation of the four ADC channels.

[0097] The channel switching module 200 includes a switching circuit for photoelectric conversion signal input and signal source input channels. This circuit connects a single photoelectric conversion signal input channel to all ADC acquisition interfaces simultaneously, while isolating other photoelectric signal input channels from the ADC acquisition input. Further, after the N photoelectric signals enter the channel switching module 200, each channel's signal is simultaneously connected to N multiplexing circuits. Each multiplexing circuit consists of N inputs and one output. Photoelectric conversion signal input channel number 1 connects to the first input of all multiplexing circuits, photoelectric signal input channel number 2 connects to the second input, and so on, with photoelectric signal input channel number M connecting to the Mth input. Only one input source of each multiplexing circuit is connected to its output at any given time. The output is connected to the ADC acquisition input signal of the sampling control module 300 for acquisition. The switching of the N input channels of the multiplexing circuit can be controlled by the processor of the sampling control module 300. Simultaneously, the multiplexing circuit module number corresponds to the photoelectric input channel number.

[0098] During the system's default operation, i.e., when no vibration signal input is detected, the photoelectric conversion input channel of serial number M is simultaneously connected to the Mth input source of all multiplexing circuits. The corresponding multiplexing circuit module of serial number M then configures the Mth input to connect to the output, and finally connects it to the corresponding serial number of the ADC acquisition channel. That is, the default signal path is that the photoelectric conversion input channel of serial number 1 is connected to the input channel 1 and output of the multiplexing circuit module of serial number 1, and then outputs to the ADC acquisition channel of serial number 1 in the sampling control module 300, and so on.

[0099] When the optical fiber in the photoelectric conversion input channel vibrates, it can be determined whether it is a single channel vibration or multiple channels vibrating simultaneously.

[0100] For single-channel vibration scenarios, the single-channel ADC hybrid sampling operation includes: when vibration is detected in the optical fiber (Ms), ADC hybrid sampling of the photoelectric conversion input channel Ms is initiated. For example, all multiplexed circuit input signal sources are switched to the Ms-th photoelectric conversion input source. At this time, the ADC acquisition channel input interfaces of all sampling control modules 300 are connected to the photoelectric conversion input signal with sequence number MS. In conjunction with the acquisition timing control circuit in the sampling control module 300, the ADC with sequence number 1 acquires the Ms-th photoelectric conversion input source. After a time period Tb = T / N, the ADC with sequence number 2 acquires the Ms-th photoelectric conversion input source, and so on. After N-1 time periods Tb, the ADC with sequence number N acquires the Ms-th photoelectric conversion input source. After another time period Tb, the acquisition by the ADC with sequence number N ends. The elapsed time period is exactly the single ADC sampling period T. Then, the ADC with sequence number 1 re-acquires the Ms-th photoelectric conversion input source. This process is repeated cyclically, with the Ms-th photoelectric conversion input source being sampled by N ADCs, increasing the sampling frequency by a factor of N, i.e., F×N. The duration T is determined based on the sampling rate F×N. hold T hold It can be determined based on prior knowledge (T) hold >0), then the ADC mixed sampling operation of channel Ms ends. The system ADC sampling signal is restored to the default multi-channel signal acquisition and sensing, that is, after each sequence number photoelectric conversion input channel is connected to the output of the corresponding sequence number multiplexing circuit module, it is connected to the sequence number corresponding to the ADC acquisition channel, and enters the default channel state.

[0101] For scenarios where multiple channels simultaneously sense vibration, the multi-channel ADC mixed sampling operation includes: the system records the number of channels Ns and their sequence numbers, and performs the ADC mixed sampling operation once for each channel with a vibration sensing signal, from smallest to largest, for a total of Ns ADC mixed sampling operations. Then, the system reverts to the default multi-channel signal acquisition and sensing state. The default operating state is maintained for a duration T. raw T raw This can be determined based on prior knowledge. Based on the vibration sensing status of each channel, if no channel has a vibration signal, sensing continues. If a channel has a vibration signal, multi-channel ADC mixed sampling is performed depending on the number of sensing channels. This process continues until the single-channel or multi-channel ADC mixed sampling operation begins or ends based on the channel vibration signal sensing status.

[0102] like Figure 5 As shown, taking a 4-channel photoelectric conversion input channel as an example, the connection includes the default connection after passing through the multiplexing circuit module and the connection of the photoelectric conversion input channel with vibration in serial number 2.

[0103] Based on the above description of the principles of the three modules, in a distributed fiber optic sensing system with multi-channel detection and sensing, when a vibration signal is detected in one of the signal channels, a time-sequential hybrid sampling technique among multiple ADC channels is used to improve the signal sampling frequency and spatial resolution without increasing system cost or data processing volume. The system can adapt to distributed fiber optic sensing systems with different signal frequencies and numbers of channels. It ensures the operation of multi-channel signals and dynamically loads the sampling rate of each ADC to the required input signal channel, maximizing the distributed fiber optic sensing system's ability to detect weak vibration signals and improve sampling spatial resolution.

[0104] In one specific embodiment, taking a 2-channel distributed fiber optic sensing DAS system as an example, such as... Figure 6 The diagram shows the functional architecture of the distributed fiber optic sensing system of this embodiment. Examples include a φ-OTDR (phase-sensitive optical time-domain reflectometer) distributed fiber optic sensing DAS system based on heterodyne coherent detection with two channels of detection.

[0105] The signal detection module 100 includes a 1550nm narrow-linewidth laser, an optical coupler (OC), an acousto-optic modulator (AOM) with an 80MHz frequency shift, an erbium-doped fiber amplifier (EDFA), and a balanced photodetector (BPD), forming two transceiver channels based on a heterodyne coherent optical path topology. Taking a 10km fiber optic cable length as an example, after system power-on, the signal detection module 100 enters standby mode, waiting for AOM start pulses from both channels. These start pulses are generated and sent by the FPGA. When the signal detection module 100 receives the AOM start pulse from the FPGA, it begins operation. The optical pulse is amplified by the EDFA and transmitted through the fiber, simultaneously generating a Rayleigh scattering signal. At this point, the balanced photodetector begins receiving the Rayleigh scattering signal and converts it into an electrical signal, which is output to the sampling control module 300. According to the heterodyne coherence principle, the frequency of the photoelectric conversion analog signal output to the sampling control module 300 is 80MHz.

[0106] The sampling control module 300 includes modules such as FPGA (Field Programmable Gate Array), DDR (Double Data Rate SDRAM), FLASH memory, high-speed operational amplifier, high-speed ADC, 400MHz high-speed reference clock, Ethernet port, and HDMI. The channel switching module 200 includes circuits for photoelectric conversion signal drive enhancement and a 2-channel 2-to-1 analog switch. Since the optical fiber is 10 kilometers long, has a refractive index of approximately 1.5, and the speed of light in the fiber is 0.2 m / ns, the time for a pulse to travel 20 kilometers round trip in the fiber is 100 µs. Based on heterodyne coherent DAS, only one pulse can exist in the optical fiber at any given time. Therefore, the upper limit of the optical pulse emission frequency for a DAS system with a 10-kilometer fiber detection length is 1 / 100 µs, or 10 kHz. In this embodiment, the working process is illustrated using a pulse width of 100 ns and a pulse frequency of 8 kHz as an example. The input signal has a center frequency of 80MHz. The sampling control module 300 selects two ADCs with an upper limit sampling rate of 200Msps (samples per second). The sampling clock frequency directly determines the sampling rate. Therefore, the ADC requires a sampling clock of 200MHz. The high-speed reference clock output is 400MHz. After system power-on, the FPGA configures the two analog switches via user control, such as... Figure 6 The dual-channel analog switch 1 is configured as fiber optic signal input channel 1 and connected to ADC1 (blue signal path in the diagram). The dual-channel analog switch 2 is configured as fiber optic signal input channel 2 and connected to ADC2 (yellow signal path in the diagram). Then, the FPGA uses a 400MHz high-speed reference clock to perform timing allocation and frequency division output for the two ADC sampling clocks. The FPGA outputs two 200MHz clocks, with a time interval of 2.5ns (one cycle of the 400MHz clock). Figure 7 As shown.

[0107] After configuring the analog switch and clock output timing, the FPGA outputs two 200MHz ADC sampling clocks with a 2.5ns interval. Simultaneously, the FPGA outputs dual AOM drive pulses to the signal detection module 100, and all modules of the system begin operation, sensing and detecting the 10km dual-channel fiber optic cable. Each channel's ADC sampling rate starts at 200Msps. When the system detects a vibration signal in the first channel's fiber optic cable, it begins the mixed sampling operation of the channel one ADC. At this time, the FPGA switches the dual-channel analog switch 2 signal source, switching the input signal from fiber optic signal input channel 2 to fiber optic signal input channel 1. After the switch, both ADC1 and ADC2 sample the photoelectric conversion signal of the first channel. At this time, the system cannot temporarily detect the fiber optic signal input channel 2. The sampling time of ADC1 is recorded as t0, with a sampling rate of 200Msps and each sampling period of 5ns. After t0+2.5ns, ADC2 samples the photoelectric conversion signal of the first channel at a sampling rate of 200Msps. After t0+2.5ns+2.5ns, ADC1 enters its second sampling period. After t0 + 2.5ns + 2.5ns + 2.5ns, ADC2 enters its second sampling cycle. This process continues, with the two ADCs sampling the first channel photoelectric conversion signal at 2.5ns intervals. The sampled signal is then converted into a digital signal and output to the FPGA for processing. At this point, the sampling rate of the first channel photoelectric conversion signal is ADC1 + ADC2, totaling 400Msps. The sampling rate has been doubled. At a sampling rate of 200Msps, a signal phase change within 5ns would be imperceptible to the system; now, at 2.5ns, the changes in the original analog signal are captured more accurately. Furthermore, light travels at a speed of 0.2m / ns, meaning a 5ns transmission distance is 1m, which translates to a system sampling spatial resolution of 1m. Using the method and circuitry of this invention, this can be doubled, reducing the system sampling spatial resolution to 0.5m. Since the DAS system provides data within seconds of sampling, the signal sensing result can be obtained. Therefore, after sampling the photoelectric conversion signal of the first channel at a sampling rate of 400Msps for a continuous period of time with a value greater than zero, the system switches the signal input source of the dual-channel analog switch 2 to the fiber optic signal input channel 2. The ADC mixed sampling operation ends, and the system reverts to its default dual-channel sensing operation. At this time, the ADC acquires the photoelectric conversion data of the two channels in real time. Waiting for a vibration sensing signal from a certain channel to be sensed, the system enters the ADC mixed sampling operation for that channel.

[0108] This embodiment provides a multi-channel photoelectric signal sampling method. By dynamically switching the signal sampling rate between channels during the sensing process, the upper limit of the sampling rate of each channel can be increased by a factor of the number of channels without changing the performance of the ADC in each channel. This improves the signal fidelity and sampling spatial resolution of each channel, thus enabling the system to adapt to more application scenarios. The sampling rate of each sensing channel in the distributed fiber optic sensing system can be switched and adjusted according to the business scenario. While ensuring the detection and sensing function of each channel, the system's ADC acquisition capability is dynamically allocated. Without increasing the cost of the ADC, the fidelity of the sensing signal and the sampling spatial resolution of the DAS system are maximized.

[0109] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0110] Based on the same inventive concept, this application also provides a distributed optical fiber sensing system for implementing the multi-channel photoelectric signal sampling method described above. The solution provided by this system is similar to the implementation described in the above method; therefore, the specific limitations in one or more distributed optical fiber sensing system embodiments provided below can be found in the limitations of the multi-channel photoelectric signal sampling method described above, and will not be repeated here.

[0111] In one embodiment, such as Figure 1 As shown, a distributed optical fiber sensing system is provided, which includes a signal detection module 100, a channel switching module 200, and a sampling control module 300; wherein:

[0112] The signal detection module 100 includes at least two photoelectric signal transceiver channels;

[0113] The sampling control module 300 includes a control unit and at least two analog-to-digital conversion acquisition channels; the at least two analog-to-digital conversion acquisition channels are connected to at least two photoelectric signal transceiver channels through a channel switching module 200; the control unit is used to execute the multi-channel photoelectric signal sampling method described above.

[0114] In one embodiment, the photoelectric signal transceiver channel includes a light source unit, an optical modulation and amplification unit, an optical signal receiving unit, a photoelectric signal conversion unit, and an optical fiber unit;

[0115] The light source unit is used to generate and emit light signals;

[0116] The optical modulation and amplification unit is used to modulate and amplify the optical signal to obtain an amplified optical signal;

[0117] The photoelectric signal conversion unit acquires the amplified optical signal through the optical signal receiving unit and the optical fiber unit in sequence; converts the optical signal into a photoelectric input signal; and sends the photoelectric input signal to the sampling control module 300 through the channel switching module 200.

[0118] In one embodiment, the sampling control module 300 further includes a pulse shaping unit, and the control unit is also used to send a pulse signal to the optical modulation and amplification unit through the pulse shaping unit; the pulse shaping unit is also used to shape the pulse signal to generate a pulse driving signal; the optical modulation and amplification unit is used to modulate and amplify the optical signal based on the pulse driving signal.

[0119] In one embodiment, the channel switching module 200 includes at least two channel switching units; the input terminal of each channel switching unit is connected to at least two photoelectric signal transceiver channels; and the output terminal of each channel switching unit is connected to the input terminal of an analog-to-digital conversion acquisition channel.

[0120] The channel switching unit is also connected to the control unit and is used to turn the channel on or off based on the channel switching command from the control unit.

[0121] The modules in the aforementioned distributed fiber optic sensing system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of the computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0122] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0123] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A multi-channel photoelectric signal sampling method, characterized in that, This method is applied to a distributed optical fiber sensing system, which includes at least two photoelectric signal transceiver channels and at least two analog-to-digital conversion acquisition channels. The multi-channel photoelectric signal sampling method includes: When the photoelectric input signal of the photoelectric signal transceiver channel meets the preset sampling conditions, the input terminals of at least two analog-to-digital conversion acquisition channels are switched to the photoelectric signal transceiver channel; Based on a preset reference clock signal, the analog-to-digital conversion acquisition channel is controlled to perform mixed sampling on the photoelectric input signal to obtain the target sampling signal; the sampling spatial resolution of the mixed sampling is an integer multiple of the sampling spatial resolution of the analog-to-digital conversion acquisition channel.

2. The multi-channel photoelectric signal sampling method according to claim 1, characterized in that, The preset sampling conditions include channel vibration conditions; the step of switching the input terminals of at least two analog-to-digital conversion acquisition channels to the photoelectric signal transceiver channel when the photoelectric input signal of the photoelectric signal transceiver channel meets the preset sampling conditions includes: When the vibration state of the signal in at least one photoelectric signal transceiver channel meets the channel vibration condition, at least two of the analog-to-digital conversion acquisition channels are switched to the photoelectric signal transceiver channel.

3. The multi-channel photoelectric signal sampling method according to claim 1, characterized in that, When there are multiple photoelectric signal transceiver channels that meet the preset sampling conditions, the step of switching at least two of the analog-to-digital conversion acquisition channels to the photoelectric signal transceiver channels includes: Record the channel number of each photoelectric signal transceiver channel that meets the preset sampling conditions in sequence; Based on the channel number, the input terminals of at least two of the analog-to-digital conversion acquisition channels are sequentially switched to the photoelectric signal transceiver channel corresponding to the channel number.

4. The multi-channel photoelectric signal sampling method according to claim 1, characterized in that, The step of controlling the analog-to-digital conversion acquisition channel to perform mixed sampling of the photoelectric input signal based on a preset reference clock signal to obtain the target sampled signal includes: The preset reference clock signal is divided by frequency to obtain at least two frequency-divided clock signals with different timing sequences; the number of frequency-divided clock signals is the same as the number of analog-to-digital conversion acquisition channels. Based on the frequency division clock signal, the analog-to-digital conversion acquisition channel is controlled to sample the photoelectric input signal to obtain a timing sampling signal; The target sampling signal is determined based on multiple timing sampling signals.

5. The multi-channel photoelectric signal sampling method according to claim 4, characterized in that, The frequency of the preset reference clock signal is the product of the sampling rate and the number of the analog-to-digital conversion acquisition channels; the step of dividing the preset reference clock signal to obtain at least two frequency-divided clock signals with different timings includes: Based on the period of the preset reference clock signal, the start time of each analog-to-digital conversion acquisition channel is determined sequentially; Based on the reference clock signal and the start time, at least two frequency-divided clock signals are generated.

6. The multi-channel photoelectric signal sampling method according to claim 1, characterized in that, The step of controlling the analog-to-digital conversion acquisition channel to perform mixed sampling of the photoelectric input signal based on a preset reference clock signal to obtain the target sampled signal includes: After a preset waiting time, the input terminal of the analog-to-digital conversion acquisition channel is switched sequentially to the preset photoelectric signal transceiver channel corresponding to the analog-to-digital conversion acquisition channel.

7. A distributed optical fiber sensing system, characterized in that, The distributed optical fiber sensing system includes a signal detection module, a channel switching module, and a sampling control module; wherein: The signal detection module includes at least two photoelectric signal transceiver channels; The sampling control module includes a control unit and at least two analog-to-digital conversion acquisition channels; the at least two analog-to-digital conversion acquisition channels are connected to the at least two photoelectric signal transceiver channels through the channel switching module; the control unit is used to execute the multi-channel photoelectric signal sampling method as described in any one of claims 1 to 6.

8. A distributed optical fiber sensing system according to claim 7, characterized in that, The photoelectric signal transceiver channel includes a light source unit, an optical modulation and amplification unit, an optical signal receiving unit, a photoelectric signal conversion unit, and an optical fiber unit; The light source unit is used to generate and emit light signals; The optical modulation and amplification unit is used to modulate and amplify the optical signal to obtain an amplified optical signal; The photoelectric signal conversion unit acquires the amplified optical signal sequentially through the optical signal receiving unit and the optical fiber unit; converts the optical signal into a photoelectric input signal; and sends the photoelectric input signal to the sampling control module through the channel switching module.

9. A distributed optical fiber sensing system according to claim 8, characterized in that, The sampling control module further includes a pulse shaping unit, and the control unit is also used to send pulse signals to the optical modulation and amplification unit through the pulse shaping unit; The pulse shaping unit is also used to shape the pulse signal to generate a pulse drive signal; The optical modulation and amplification unit is used to modulate and amplify the optical signal based on the pulse drive signal.

10. A distributed optical fiber sensing system according to claim 7, characterized in that, The channel switching module includes at least two channel switching units; the input terminal of each channel switching unit is connected to at least two of the photoelectric signal transceiver channels; the output terminal of each channel switching unit is connected to the input terminal of one of the analog-to-digital conversion acquisition channels. The channel switching unit is also connected to the control unit and is used to turn on or off based on the channel switching command of the control unit.

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