WO2020243993A1

WO2020243993A1 - Photoelectric composite geophone and detection system

Info

Publication number: WO2020243993A1
Application number: PCT/CN2019/091794
Authority: WO
Inventors: 刘奇; 陈绍杰; 尹大伟; 冯帆
Original assignee: 山东科技大学
Priority date: 2019-06-06
Filing date: 2019-06-18
Publication date: 2020-12-10
Also published as: ZA201906654B; NL2024176B1; CN110244348A; CN110244348B

Abstract

A photoelectric composite geophone (1), comprising a housing (101), an optical fiber detection assembly (102) and a piezoelectric detection assembly (103). The optical fiber detection assembly (102) comprises a first compliant cylinder (1021) and a second compliant cylinder (1022), which are coaxially arranged, and a first optical fiber (1023) fixedly wound around the first compliant cylinder (1021) in a clockwise manner, and a second optical fiber (1024) fixedly wound around the second compliant cylinder (1022) in an anticlockwise manner. The piezoelectric detection assembly (103) is located between a lower end face of the first compliant cylinder (1021) and an upper end face of the second compliant cylinder (1022), and comprises a detection base (1031), a first piezoelectric piece (1032) fixedly arranged on an upper surface of the detection base (1031), a second piezoelectric piece (1033) fixedly arranged on a lower surface of the detection base (1031), and an electrical signal transmission line (1034) electrically connected to the first piezoelectric piece (1032) and the second piezoelectric piece (1033). By means of simultaneous measurement of seismic waves by combining the optical fiber detection assembly (102) with the piezoelectric detection assembly (103), the photoelectric composite geophone (1) can more accurately obtain an actual parameter of a vibration signal and has higher accuracy and credibility.

Description

Photoelectric composite geophone and detection system

This disclosure is based on a Chinese patent application with an application number of 201910488689.X and an application date of June 6, 2019, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby incorporated into this application by reference

Technical field

The invention relates to the technical field of seismic detection, in particular to a photoelectric composite geophone and a detection system.

Background technique

Seismic exploration is currently one of the most commonly used methods of petroleum exploration and underground coal mine physical detection. It mainly uses the vibration signal generated by the artificial seismic source in the stratum. Geophones are placed at different positions from the seismic source to collect the vibration signal, and then the signal is corresponding Data processing.

Geophones are commonly used vibration sensors in seismic exploration. As the front-end equipment for signal reception and acquisition, their characteristic parameters directly affect the accuracy of seismic data acquisition results. Multi conventional electromagnetic geophone, electromagnetic detector having a strong anti-interference, short response time, ability strong linear properties, electrical conventional geophones or seismometers accelerometer equivalent noise generally μg · Hz ^{- 1/2} or even below the order of ng·Hz ^-1/2 , the disadvantage of electromagnetic detectors is that they require continuous power supply during measurement and are difficult to use in harsh monitoring environments. The existing geophones also have optical fiber type, which can make up for the shortcomings of electromagnetic type, but the measurement range of optical fiber type geophone is 5-800Hz, and it cannot measure the vibration of rock burst (frequency 0-10Hz).

Summary of the invention

Aiming at the technical problems in the prior art, the present invention provides a photoelectric composite geophone.

A photoelectric composite geophone includes a casing, an optical fiber detection component and a piezoelectric detection component installed inside the casing, wherein:

The optical fiber detector assembly includes a first coaxially-arranged cylinder, a second coaxial cylinder, and a first optical fiber fixedly wound on the first coaxial cylinder clockwise, and a first optical fiber fixedly wound on the second coaxial cylinder counterclockwise. The second optical fiber; one end of the first optical fiber and the second optical fiber are both connected to an external light source, and the other end is equipped with a reflector;

The piezoelectric detection component is located between the lower end surface of the first compliant cylinder and the upper end surface of the second compliant cylinder, and the piezoelectric detection component includes a detection substrate, and a first piezoelectric sheet fixedly arranged on the upper surface of the detection substrate is fixedly arranged on the detection substrate. The second piezoelectric sheet on the lower surface of the base body, an electrical signal transmission line electrically connected to the first piezoelectric sheet and the second piezoelectric sheet;

The optical fiber detection component detects the seismic signal and transmits the corresponding optical signal to the outside through the first optical fiber and the second optical fiber, and the piezoelectric detection component detects the seismic signal and transmits the corresponding electrical signal to the outside through the electrical signal transmission line.

Further, both the first cis-changing cylinder and the second cis-changing cylinder are cylindrical silica gel cylinders.

Further, it further comprises a first base and a second base for limiting the range of movement of the first and second compliant cylinders, wherein:

The first base is installed between the upper end surface of the first compliant cylinder and the housing;

The second base is installed between the lower end surface of the second compliant cylinder and the shell.

Further, it also includes a first spring and a second spring, wherein:

The first spring is installed between the first base and the first compliant cylinder;

The second spring is installed between the second base and the second compliant cylinder.

Further, it also includes a protective filler filled between the shell and the side surface of the first compliant cylinder and the side surface of the second compliant cylinder.

Further, the first compliant cylinder, the piezoelectric detector assembly, and the second compliant cylinder are provided with a signal transmission channel of equal radius in the axial direction, and the first optical fiber, the second optical fiber, and the electrical signal transmission line transmit optical signals outward through the signal transmission channel. Or electrical signals.

Further, the first optical fiber and the second optical fiber are both single-mode optical fibers.

An earthquake detection system includes a photoelectric composite geophone, a laser light source, a coupler connected between the laser light source and the photoelectric composite geophone, an optical signal processing unit connected with the coupler, and a photoelectric composite geophone The signal conversion unit electrically connected to the signal converter, the upper computer electrically connected to the signal conversion unit, where:

The photoelectric composite geophone is the above-mentioned photoelectric composite geophone;

The first optical fiber and the second optical fiber are connected to the coupler, and the optical signal is sent to the optical signal processing unit for calculation processing;

The electrical signal transmission line is electrically connected with the signal conversion unit, and the signal conversion unit converts the electrical signal and sends it to the upper computer for calculation processing.

Further, the detection system includes at least two photoelectric composite geophones.

Further, the optical signal processing unit and the host computer both process the optical signal and the electrical signal through wavelet packet denoising.

The photoelectric composite geophone of this embodiment can measure the seismic waves at the same time by combining the optical fiber detector component and the piezoelectric detector component, so that the actual parameters of the vibration signal can be obtained more accurately, and it has higher accuracy and reliability; On the one hand, the first optical fiber that is wound clockwise on the first coaxial cylinder and the second optical fiber that is wound counterclockwise on the second covariant cylinder in the optical fiber detection assembly form a differential measurement relationship, and the optical signals generated respectively are The difference can eliminate most of the interference signals, so the structural design of the optical fiber detector assembly is reasonable, and the accuracy of the measured results is high; on the other hand, the piezoelectric detector assembly uses the piezoelectric effect on the basis of the designed optical fiber detector assembly. The principle converts the vibration information of the environment where the first compliant cylinder and the second compliant cylinder are located into electrical signals for collection. As another measurement method of vibration information, the piezoelectric detector can measure tiny deformation information, so the response speed Fast and strong in receiving high frequency signals.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings may be obtained from these drawings without creative work.

Fig. 1 is a schematic diagram of the internal structure of a photoelectric composite geophone according to an embodiment of the present invention;

Figure 2 is a schematic cross-sectional view of a photoelectric composite geophone according to an embodiment of the present invention;

Figure 3 is a structural composition diagram of an earthquake detection system according to an embodiment of the present invention;

Among them: 1-photoelectric composite geophone, 101-housing, 102-fiber detector assembly, 1021-first cis-changing cylinder, 1022-second cis-changing cylinder, 1023-first optical fiber, 1024-second optical fiber, 103 -Piezoelectric detection component, 1031-detection base, 1032-first piezoelectric sheet, 1033-second piezoelectric sheet, 1034-electric signal transmission line, 104-first base, 105-second base, 106-th One spring, 107-second spring, 108-protection filler, 109-signal transmission channel, 2-laser light source, 3-coupler, 4-optical signal processing unit, 5-signal conversion unit, 6-upper computer.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

As shown in Figures 1 and 2, an optoelectronic composite geophone 1 according to an embodiment of the present invention includes a housing 101, a fiber detection component 102 and a piezoelectric detection component 103 installed inside the housing 101, in which:

The optical fiber detection assembly 102 includes a first coaxially-arranged cylinder 1021, a second coaxial cylinder 1022, and a first optical fiber 1023 fixedly wound on the first coaxial cylinder 1021 clockwise, and fixedly wound on the second The second optical fiber 1024 on the compliant cylinder 1022; one end of the first optical fiber 1023 and the second optical fiber 1024 are both connected to an external light source, and the other end is equipped with a reflector; the piezoelectric detection component 103 is located on the lower end surface of the first compliant cylinder 1021 The piezoelectric detector assembly 103 includes a detection base 1031, a first piezoelectric sheet 1032 fixedly arranged on the upper surface of the detection base 1031, and a second piezoelectric plate 1032 fixedly arranged on the lower surface of the detection base 1031. Piezoelectric sheet 1033, an electrical signal transmission line 1034 electrically connected to the first piezoelectric sheet 1032 and the second piezoelectric sheet 1033; the optical fiber detection component 102 detects the seismic signal and transmits the corresponding optical signal through the first optical fiber 1023 and the second optical fiber 1024 External transmission, the piezoelectric detection component 103 detects the seismic signal and transmits the corresponding electrical signal to the outside through the electrical signal transmission line 1034.

In the optical fiber detection assembly 102 of this embodiment, the optical signal used for detection is input through one end of the first optical fiber 1023 and the second optical fiber 1024, and the light is transmitted through a mirror provided at the other end of the first optical fiber 1023 and the second optical fiber 1024. The signal returns, and the returned optical signal is used as the measurement signal for the next processing and analysis. When the first compliant cylinder 1021 and the second compliant cylinder 1022 are relatively displaced under the action of seismic waves, the optical fiber detector assembly 102 of this embodiment converts the change of the physical field into the radial strain and the longitudinal strain of the optical fiber, so the first The optical signals transmitted from the first optical fiber 1023 and the second optical fiber 1024 contain measurement information corresponding to the strain effect, and the measurement information is analyzed and calculated to obtain the measurement result. In this embodiment, the winding directions of the first optical fiber 1023 and the second optical fiber 1024 are opposite. During a certain detection period, the first compliant cylinder 1021 and the second compliant cylinder 1022 receive the same force, but they are transformed into fiber strain. During the process, the correspondingly generated optical signals are not the same. After the optical signals of the first optical fiber 1023 and the second optical fiber 1024 are output, more accurate measurement results can be obtained by differential operation, and the transmission of the optical fiber detection component 102 is also increased.感性。 Sensitivity.

In this embodiment, the first compliant cylinder 1021 and the second compliant cylinder 1022 are used as transducer elements, which have the characteristic of low elastic coefficient. Therefore, the natural frequency of the optical fiber detection assembly 102 is relatively low and is more suitable for detection of low frequency seismic waves. The first compliant cylinder 1021 and the second compliant cylinder 1022 in this embodiment can be made of silica gel, and the external shape is designed as a cylinder. The first optical fiber 1023 and the second optical fiber 1024 in this embodiment adopt a small radius of curvature. Single-mode fiber. In this embodiment, the first optical fiber 1023 is wound clockwise on the first coaxial cylinder 1021. Correspondingly, the second optical fiber 1024 is wound on the second coaxial cylinder 1022 counterclockwise. The first optical fiber is not specifically limited here. 1023 or the head end and tail end of the second optical fiber 1024, just indicate that the winding directions of the first optical fiber 1023 and the second optical fiber 1024 are opposite, and differential measurement can be achieved. The specific winding method is designed by those skilled in the art in practice. Yes, except for different winding directions, the same working parameters should be selected as much as possible to ensure that the measurement error is minimized.

The piezoelectric detector component 103 in this embodiment is located between the lower end surface of the first compliant cylinder 1021 and the upper end surface of the second compliant cylinder 1022, and separates the first compliant cylinder 1021 and the second compliant cylinder 1022 in two Detect separately in the cavity. The upper surface and the lower surface of the detection base 1031 of this embodiment are respectively fixedly provided with a first piezoelectric sheet 1032 and a second piezoelectric sheet 1033. When the first compliant cylinder 1021 is displaced by seismic waves, the first piezoelectric sheet 1032 is generated. Pressure, when the second compliant cylinder 1022 is displaced by seismic waves, pressure is generated on the second piezoelectric sheet 1033; the first piezoelectric sheet 1032 and the second piezoelectric sheet 1033 output detection signals to the outside through the electrical signal transmission line 1034. This embodiment does not limit the specific product models of the first piezoelectric sheet 1032 and the second piezoelectric sheet 1033, and one or more sets of piezoelectric ceramic sheets can be used to achieve the design objectives of this solution.

Specifically, on the basis of the previous embodiment, the photoelectric composite geophone 1 of this embodiment further includes a first base 104 and a first base 104 for limiting the amplitude of movement of the first compliant cylinder 1021 and the second compliant cylinder 1022 The second base 105, wherein: the first base 104 is installed between the upper end surface of the first compliant cylinder 1021 and the housing 101; the second base 105 is installed between the lower end surface of the second compliant cylinder 1022 and the housing 101. As shown in FIG. 1, the design purpose of the first base 104 and the second base 105 is to limit the range of movement of the first compliant cylinder 1021 and the second compliant cylinder 1022. Since the first optical fiber 1023 and the second optical fiber 1024 change the optical phase of the transmitted optical signal through their radial or longitudinal deformation, in order to ensure that the measurement of the first optical fiber 1023 and the second optical fiber 1024 can be within the normal measurement range , The vibration amplitude of the first compliant cylinder 1021 and the second compliant cylinder 1022 needs to be limited. The first base 104 and the second base 105 of this embodiment can be made of metal, such as aluminum; both the first base 104 and the second base 105 are fixed on the housing 101, and the housing 101 and the first base 105 A sealing ring can be arranged between the seat 104 and the second base 105 to ensure the sealing of the internal components of the housing.

Specifically, as shown in FIGS. 1 and 2, the photoelectric composite geophone 1 of this embodiment further includes a first spring 106 and a second spring 107, wherein: the first spring 106 is mounted on the first base 104 and the second base 104 Between a compliant cylinder 1021; the second spring 107 is installed between the second base 105 and the second compliant cylinder 1022. In order to ensure that the first compliant cylinder 1021 and the second compliant cylinder 1022 are displaced due to vibration, the first spring 106 and the second spring 107 in this embodiment are respectively connected to the first compliant cylinder 1021 and the second compliant cylinder 1022. There is elastic force between 1022, so the first spring 106 restores the first compliant cylinder 1021 to the original position, and the second spring 107 restores the second compliant cylinder 1022 to the original position, which improves the accuracy of subsequent detection.

Specifically, as shown in FIGS. 1 and 2, the photoelectric composite geophone 1 of this embodiment further includes a protective filling filled between the housing 101 and the side surfaces of the first compliant cylinder 1021 and the second compliant cylinder 1022物108. The protective filler 108 of this embodiment can have a certain limitation and cushioning effect on the moving space of the first compliant cylinder 1021 and the second compliant cylinder 1022, and generally can be realized by using polyurethane material.

Specifically, as shown in FIGS. 1 and 2, the first compliant cylinder 1021, the piezoelectric detector component 103, and the second compliant cylinder 1022 in this embodiment are provided with a signal transmission channel 109 of equal radius in the axial direction. An optical fiber 1023, a second optical fiber 1024, and an electrical signal transmission line 1034 transmit optical signals or electrical signals outward through the signal transmission channel 109. The transmission of optical signals relies on the first optical fiber 1023 and the second optical fiber 1024, and the transmission of electrical signals relies on the electrical signal transmission line 1034. In order to make the structure of the entire photoelectric composite geophone 1 more compact and beautiful, the embodiment is set in the axial direction There is a signal transmission channel 109, the first optical fiber, 1023, the second optical fiber 1024 and the electrical signal transmission line 1034 realize the transmission of measurement information through the signal transmission channel 109.

Specifically, the first optical fiber 1023 and the second optical fiber 1024 in the embodiment of the present invention are both single-mode optical fibers. Compared with multi-mode fiber, single-mode fiber has the advantages of low dispersion and low loss. At the same time, single-mode fiber is extremely sensitive to external magnetic field, vibration, acceleration, temperature, etc., and has higher sensitivity when applied in this solution.

As shown in Figure 3, another embodiment of the present invention is an earthquake detection system, which includes a photoelectric composite geophone 1, a laser light source 2, and a coupler 3 connected between the laser light source 2 and the photoelectric composite geophone 1. , The optical signal processing unit 4 connected to the coupler 3, the signal conversion unit 5 electrically connected to the photoelectric composite geophone 1, the upper computer 6 electrically connected to the signal conversion unit 5, of which: the photoelectric composite geophone 1 It is the photoelectric composite geophone 1 in the above embodiment; the first optical fiber 1023 and the second optical fiber 1024 are connected to the coupler 3, and the optical signal is sent to the optical signal processing unit 4 for calculation processing; the electrical signal transmission line 1034 is connected to the signal The conversion unit 5 is electrically connected, and the signal conversion unit 5 converts the electrical signal and sends it to the upper computer 6 for calculation processing.

The specific working process of the earthquake detection system of this embodiment is as follows: the laser light source 2 emits a laser beam to the coupler 3. In this embodiment, between the laser light source 2 and the coupler 3, and between the coupler 3 and the optical signal processing unit 4 The optical signal transmission is realized by optical fiber; the coupler 3 divides the laser beam into two beams and transmits measurement by the first optical fiber 1023 and the second optical fiber 1024 respectively; the optical signal is transmitted to the end of the first optical fiber 1023 or the second optical fiber 1024 by reflection The mirror reflects and returns according to the original transmission path; in the process of optical signal transmission, if the external vibration occurs, the first optical fiber 1023 or the second optical fiber 1024 will be deformed, which will affect the optical phase of the optical signal; when the coupler 3 receives the first optical fiber After the optical signals returned by the first optical fiber 1023 and the second optical fiber 1024, the two measurement lights are integrated and sent to the optical signal processing unit 4 for analysis and calculation. At the same time, the first piezoelectric sheet 1032 and the second piezoelectric sheet 1033 generate corresponding electrical signals after being pressed by the first compliant cylinder 1021 and the second compliant cylinder 1022, which are transmitted to the signal through the electrical signal transmission line 1034 The conversion unit 5, the signal conversion unit 5 converts the electrical signal into a digital signal, and the upper computer 6 performs calculation and analysis. The optical signal processing unit 4 of this embodiment has a function of converting optical signals into electrical signals or digital signals, and can perform further calculation and analysis on the converted signals. Preferably, the optical signal processing unit 4 of this embodiment is connected to the upper computer 6, and the upper computer 6 performs unified calculation and analysis on the measurement data corresponding to the optical signal and the measurement data corresponding to the electrical signal, and the calculation and statistics of multiple sets of data will be obtained The correlation between these two measurement methods is shown, and then more accurate measurement results can be obtained.

Specifically, the detection system in this embodiment includes at least two photoelectric composite geophones 1. In order to make the measurement results of the photoelectric composite geophone 1 more accurate, this embodiment sets at least two photoelectric composite geophones 1 to perform simultaneous measurements, and the measured optical signals are analyzed and processed by the optical signal processing unit 4 in a unified manner. The electrical signal is processed by the host computer 6. The more photoelectric composite geophones 1 are installed in the detection system of this embodiment, the more the measured results are more realistic and the reliability is higher.

Specifically, the optical signal processing unit 4 and the host computer 6 of this embodiment both process optical signals and electrical signals through wavelet packet denoising. In the process of signal acquisition, due to the influence of the surrounding environment, the collected data must be mixed with noise, so before analyzing the signal, it needs to be denoised to reduce interference and restore the real signal, which is convenient for the feature extraction of the real signal. The specific steps of wavelet packet denoising are as follows:

(1) Determine the wavelet base by the "entropy" criterion;

(2) Determine the number of levels N of signal decomposition;

(3) Set threshold for the decomposition coefficient of each layer;

(4) Reconstruct the processed signal to obtain the real signal.

When denoising the signal, the selected wavelet base should meet the following principles as much as possible: ①Symmetry, ②Regularity, which can effectively reduce the possibility of phase distortion of the decomposed signal, and make the reconstructed signal true and smooth. Through a large number of experiments, when the sym6 wavelet is selected, the reconstructed waveform of the decomposed signal can reflect the original signal as a whole; at the same time, the number of layers of wavelet packet decomposition is another important parameter, which determines the amount of calculation of the system during decomposition. As the number of decomposition layers increases, the denoising effect tends to change from strong to unchanged. At the same time, the amount of calculation will increase exponentially with the increase of the number of decomposition layers. This requires experiments to obtain the best number of decomposition layers. Wavelet packet denoising has a stronger ability to decompose the signal. The high-frequency and low-frequency information of the signal can be obtained at the same time during decomposition, making the reconstructed signal closer to the original signal.

The present invention has been further described above with the help of specific embodiments, but it should be understood that the specific description here should not be construed as limiting the essence and scope of the present invention. Those of ordinary skill in the art will comment on the above after reading this specification. Various modifications made to the embodiments fall within the protection scope of the present invention.

Claims

A photoelectric composite geophone, which is characterized by comprising a housing, an optical fiber detection component and a piezoelectric detection component installed inside the housing, wherein:

The optical fiber detection assembly includes a first coaxially-arranged cylindrical body, a second cylindrical body, and a first optical fiber that is fixedly wound clockwise on the first cylindrical body, and is fixedly wound on the first optical fiber counterclockwise. Two second optical fibers on the cis-shifting cylinder; one end of the first optical fiber and the second optical fiber are both connected to an external light source, and the other end is provided with a reflector;

The piezoelectric detection component is located between the lower end surface of the first compliant cylinder and the upper end surface of the second compliant cylinder, and the piezoelectric detection component includes a detection base fixedly arranged on the upper surface of the detection base A first piezoelectric sheet, a second piezoelectric sheet fixedly arranged on the lower surface of the detection base, and an electrical signal transmission line electrically connected to the first piezoelectric sheet and the second piezoelectric sheet;

The optical fiber detection component detects the seismic signal and transmits the corresponding optical signal to the outside through the first optical fiber and the second optical fiber, and the piezoelectric detection component detects the seismic signal and transmits the corresponding electrical signal through the electrical signal transmission line. External transmission.
The photoelectric composite geophone of claim 1, wherein the first compliant cylinder and the second compliant cylinder are both cylindrical silica gel cylinders.
The photoelectric composite geophone according to claim 2, further comprising a first base and a second base for limiting the amplitude of movement of the first compliant cylinder and the second compliant cylinder. Base, where:

The first base is installed between the upper end surface of the first compliant cylinder and the housing;

The second base is installed between the lower end surface of the second compliant cylinder and the housing.
The photoelectric composite geophone of claim 3, further comprising a first spring and a second spring, wherein:

The first spring is installed between the first base and the first compliant cylinder;

The second spring is installed between the second base and the second compliant cylinder.
The photoelectric composite geophone according to claim 3, further comprising a protective filler filled between the outer shell and the side surface of the first compliant cylinder and the side surface of the second compliant cylinder Things.
The photoelectric composite geophone according to claim 5, wherein the first compliant cylinder, the piezoelectric detector assembly, and the second compliant cylinder are provided with signals of equal radius in the axial direction. Transmission channel, the first optical fiber, the second optical fiber, and the electrical signal transmission line transmit optical signals or electrical signals outward through the signal transmission channel.
The photoelectric composite geophone of claim 1, wherein the first optical fiber and the second optical fiber are both single-mode optical fibers.
An earthquake detection system, characterized in that it comprises a photoelectric composite geophone, a laser light source, a coupler connected between the laser light source and the photoelectric composite geophone, and a light source connected to the coupler A signal processing unit, a signal conversion unit electrically connected to the photoelectric composite geophone, an upper computer electrically connected to the signal conversion unit, wherein:

The photoelectric composite geophone is the photoelectric composite geophone according to any one of claims 1-7;

The first optical fiber and the second optical fiber are connected to the coupler, and the optical signal is sent to the optical signal processing unit for calculation processing;

The electrical signal transmission line is electrically connected to the signal conversion unit, and the signal conversion unit converts the electrical signal and sends it to the host computer for calculation processing.
The seismic detection system according to claim 8, wherein said detection system comprises at least two said photoelectric composite geophones.
9. The seismic detection system of claim 9, wherein the optical signal processing unit and the upper computer both process optical and electrical signals through wavelet packet denoising.