A microseismic sensor front-end signal conditioning circuit based on lag correction frequency expansion

Abstract

The present disclosure relates to the technical field of signal processing, and particularly relates to a microseismic sensor front-end signal conditioning circuit based on lag correction frequency expansion. The microseismic sensor front-end signal conditioning circuit based on lag correction frequency expansion comprises: a differential amplification circuit, which is used for converting a differential signal input by a microseismic sensor into a single-ended vibration signal, and pre-amplifying the vibration signal according to a preset gain to obtain an amplified vibration signal; a filtering and lag correction circuit, which is used for widening the frequency range of the amplified vibration signal through filtering and lag correction to obtain a conditioned vibration signal. The present disclosure adopting the above scheme can expand the frequency of a magneto-electric sensor through low-frequency compensation technology, and improve the response capability of the magneto-electric sensor to low-frequency signals.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of signal processing, in particular to a microseismic sensor front-end signal conditioning circuit based on lag correction frequency extension. BACKGROUND

[0002] With the increase of coal mining depth, the frequency and disaster-causing of mine earthquake are becoming more and more serious. Mine earthquake is a kind of microseismic phenomenon caused by mining disturbance, which makes the coal and rock mass accumulate and release a large amount of elastic energy in a short time. It is not only a kind of underground disaster, but also a dynamic source of other coal and rock dynamic disasters. In order to effectively prevent mine earthquake disasters, microseismic monitoring systems are widely used to obtain coal and rock mass rupture vibration signals, and then to locate the source and study the distribution law of mine earthquake, and even to invert the information of geological structure, coal and rock fracture, stress distribution near the source. The lower the frequency of the vibration signal, the slower it decays in the coal and rock layer, so the low-frequency vibration signal has a longer propagation distance and a larger influence range. The characteristics of mine earthquake wave are large energy and low frequency concentration, which requires the microseismic monitoring system to have good response to low-frequency vibration signals.

[0003] The first to receive the vibration wave signal in the microseismic monitoring system is the vibration sensor. The pickup ability of the sensor to different frequency signals directly determines the overall frequency response range of the microseismic monitoring system, and the frequency response range of the microseismic sensor should cover 0.1-600Hz. Limited by the severe working environment in coal mine, the vibration sensor used in the current microseismic monitoring system is generally a magneto-electric sensor which has the advantages of adapting to complex environment, mature technology, high economic benefit and being suitable for large-scale installation. However, the magneto-electric vibration sensor has attenuation performance to signals below its natural frequency, and due to the limitation of its own mechanical structure, the traditional magneto-electric microseismic sensor cannot simultaneously meet the characteristics of good low-frequency response, appropriate size and quality, and long-term stable work, and it is difficult to effectively pick up low-frequency vibration signals below 1Hz. In order to solve the above problems, it is necessary to extend the frequency of the magneto-electric sensor through low-frequency compensation technology to improve its response ability to low-frequency signals. SUMMARY

[0004] The present disclosure provides a microseismic sensor front-end signal conditioning circuit based on lag correction frequency extension, which mainly aims to extend the frequency of the magneto-electric sensor through low-frequency compensation technology to improve its response ability to low-frequency signals.

[0005] According to an aspect of the present disclosure, a microseismic sensor front-end signal conditioning circuit based on lag correction frequency extension is provided, comprising:

[0006] a differential amplification circuit, configured to convert a differential signal input by a microseismic sensor into a single-ended vibration signal, and pre-amplify the vibration signal according to a preset gain to obtain an amplified vibration signal;

[0007] The filter and lag correction circuit is configured to widen the frequency range of the amplified vibration signal by means of filtering and lag correction, and obtain a conditioned vibration signal.

[0008] Optionally, in an embodiment of the present disclosure, the circuit further comprises:

[0009] The damping ratio correction circuit is configured to receive an initial differential signal input by the microseismic sensor, and correct the initial differential signal to obtain a corrected differential signal, and input the corrected differential signal to the differential amplification circuit.

[0010] Optionally, in an embodiment of the present disclosure, the damping ratio correction circuit comprises a first resistor; wherein,

[0011] The positive output end of the microseismic sensor is connected with the first end of the first resistor and the positive input end of the differential amplification circuit respectively, and the negative output end of the microseismic sensor is connected with the second end of the first resistor and the negative input end of the differential amplification circuit respectively.

[0012] Optionally, in an embodiment of the present disclosure, the differential amplification circuit comprises a first operational amplifier; wherein,

[0013] The positive input end of the first operational amplifier is connected with the positive output end of the microseismic sensor, the negative input end of the first operational amplifier is connected with the negative output end of the microseismic sensor, and the output end of the first operational amplifier is connected with the input end of the filter and lag correction circuit.

[0014] Optionally, in an embodiment of the present disclosure, the filter and lag correction circuit comprises:

[0015] The high-pass filter circuit is configured to perform high-pass filtering on the amplified vibration signal to obtain a high-pass filtered vibration signal.

[0016] The first-stage lag correction circuit is configured to perform lag correction on the high-pass filtered vibration signal to obtain a lag-corrected vibration signal.

[0017] The second-stage lag correction circuit is configured to perform secondary lag correction on the lag-corrected vibration signal to obtain a secondary lag-corrected vibration signal.

[0018] The low-pass filter circuit is configured to perform low-pass filtering on the secondary lag-corrected vibration signal to obtain the conditioned vibration signal.

[0019] Optionally, in an embodiment of the present disclosure, the high-pass filter circuit comprises a first capacitor; wherein,

[0020] The first end of the first capacitor is connected with the output end of the differential amplification circuit, and the second end of the first capacitor is connected with the input end of the first stage lag correction circuit.

[0021] Optionally, in an embodiment of the present disclosure, the first stage lag correction circuit comprises a second capacitor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a second operational amplifier; wherein,

[0022] The first end of the second resistor is connected with the output end of the high-pass filter circuit, the second capacitor and the third resistor are connected in series to form a first series branch, the second end of the second resistor is connected with the negative input end of the second operational amplifier, the first end of the first series branch, and the first end of the fourth resistor respectively, the second end of the fourth resistor is connected with the first end of the fifth resistor and the first end of the sixth resistor respectively, and the connection point between the second end of the first series branch, the second end of the fifth resistor, and the output end of the second operational amplifier is connected with the input end of the second stage lag correction circuit; the positive input end of the second operational amplifier and the second end of the sixth resistor are grounded.

[0023] Optionally, in an embodiment of the present disclosure, the second stage lag correction circuit comprises a third capacitor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, and a third operational amplifier; wherein,

[0024] The first end of the seventh resistor is connected with the output end of the first stage lag correction circuit, the third capacitor and the eighth resistor are connected in series to form a second series branch, the second end of the seventh resistor is connected with the negative input end of the third operational amplifier, the first end of the second series branch, the first end of the ninth resistor, and the first end of the low-pass filter circuit respectively, the second end of the ninth resistor is connected with the first end of the tenth resistor and the first end of the eleventh resistor respectively, the connection point between the second end of the second series branch, the second end of the tenth resistor, the output end of the third operational amplifier, and the second end of the low-pass filter circuit is the output end of the filter and lag correction circuit; the positive input end of the third operational amplifier and the second end of the eleventh resistor are grounded.

[0025] Optionally, in an embodiment of the present disclosure, the low-pass filter circuit comprises a fourth capacitor; wherein,

[0026] The first end of the fourth capacitor is connected with the second end of the seventh resistor, the negative input end of the third operational amplifier, the first end of the second series branch and the first end of the ninth resistor respectively, and the connection point between the second end of the second series branch, the second end of the tenth resistor, the output end of the third operational amplifier and the second end of the fourth capacitor is the output end of the filter and hysteresis correction circuit.

[0027] Optionally, in an embodiment of the present disclosure, the circuit further comprises:

[0028] a control circuit configured to adjust the preset gain in the differential amplification circuit;

[0029] The control circuit is further configured to adjust a filter parameter and a hysteresis correction parameter in the filter and hysteresis correction circuit, so that the filter and hysteresis correction circuit widens the frequency range of the amplified vibration signal to a preset frequency range corresponding to the filter parameter and the hysteresis correction parameter, to obtain a conditioned vibration signal.

[0030] In summary, the microseismic sensor front-end signal conditioning circuit based on hysteresis correction frequency widening provided by the embodiments of the present disclosure can effectively filter out such noise interference and better receive effective signals by connecting a differential amplification circuit in series at the output end of the sensor. In addition, the filter and hysteresis correction circuit obtained by combining the filter circuit and the hysteresis correction compensation circuit can reduce the number of operational amplifiers, simplify the overall structure of the circuit, and reduce the influence of noise. Secondly, by using the hysteresis correction compensation and filter principle technology for frequency widening, the lower limit of the frequency range of the sensor monitoring vibration signal can be widened, and the upper limit of the frequency range of the sensor monitoring vibration signal can be preserved to the greatest extent. The low-frequency compensation technology can be used to widen the frequency of the magneto-electric sensor and improve its response capability to low-frequency signals.

[0031] Additional aspects and advantages of the present disclosure will be made apparent from the following description, which, taken together with the accompanying drawings, describes an embodiment of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0032] The above and / or additional aspects and advantages of the present disclosure will become apparent and more readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0033] Figure 1 A structural schematic diagram of a microseismic sensor front-end signal conditioning circuit based on hysteresis correction frequency widening provided by an embodiment of the present disclosure;

[0034] Figure 2 A structural schematic diagram of a microseismic sensor front-end signal conditioning circuit based on hysteresis correction frequency widening provided by another embodiment of the present disclosure;

[0035] Figure 3 A structure diagram of a damping ratio correction circuit and a differential amplification circuit provided by an embodiment of the present disclosure;

[0036] Figure 4 A structure diagram of a filtering and lag correction circuit provided by an embodiment of the present disclosure;

[0037] Figure 5 A second-order lag correction system amplitude-frequency characteristic curve diagram provided by an embodiment of the present disclosure;

[0038] Figure 6 An amplitude-frequency characteristic curve diagram of a microseismic sensor front-end signal conditioning circuit based on lag correction frequency expansion provided by an embodiment of the present disclosure;

[0039] Figure 7 A frequency expansion before and after vibration sensor amplitude-frequency characteristic curve diagram provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0040] Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. The same or similar components or components having the same or similar functions are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are for the purpose of explaining the present disclosure only, and should not be understood as limiting the present disclosure. On the contrary, embodiments of the present disclosure include all changes, modifications and equivalents falling within the spirit and scope of the appended claims.

[0041] It should be noted that the current relatively mature low-frequency compensation technology of magneto-electric sensor includes passive servo compensation, series compensation, feedback compensation, negative resistance compensation, system identification compensation, etc. Considering the application scene of microseismic monitoring, the low-frequency signal pickup ability of the sensor after compensation is improved, but there are still other deficiencies. For example: (1) Different low-frequency compensation methods have problems such as reducing the sensitivity of the sensor, complicating the structure, or sacrificing the upper limit of the monitoring frequency band; (2) The underground coal mine is full of complex noise interference. The active low-frequency compensation circuit can improve the anti-interference ability of the sensor by adding a differential amplification circuit. However, the pre-set parameters may cause the loss of weak signals or the excessive amplification of strong signals if they are not appropriate; (3) The low-frequency compensation method with good frequency extension effect is usually a cascade structure of operational amplifiers, but it will amplify the circuit background noise and affect the judgment of effective signals; (4) The lower the expected lower limit of the frequency band, the larger the resistance value in the circuit. The mismatch between large resistance and small capacitance not only causes signal distortion, but also introduces high electronic noise; (5) The low-frequency compensation technology of pure analog circuit has high requirements for model and parameter accuracy. The application cannot be adjusted, and the sensor with fixed parameters also needs an analog circuit with fixed parameters to correspond. Although the low-frequency compensation technology of pure digital circuit can dynamically adjust the circuit parameters, it has the problems of high quantization error and delay, which cannot fully meet the real-time requirements of coal mine microseismic monitoring.

[0042] Specifically, different types of magneto-electric vibration sensor frequency extension technologies have their own problems:

[0043] (1) Passive servo compensation reduces the sensitivity of the sensor and increases the damping ratio, and the frequency extension effect is not ideal.

[0044] (2) Electronic feedback compensation reduces the damping ratio of the sensor, and the frequency extension range is limited; force balance feedback compensation technology has high technical requirements and high cost.

[0045] (3) Negative resistance compensation needs to introduce negative inductance at the same time, and the circuit structure is extremely complex and difficult to implement.

[0046] (4) System identification compensation requires high computing power, and has the problems of quantization error and poor real-time performance.

[0047] (5) Zero-pole configuration method needs accurate mathematical model and will sacrifice the response ability of middle and high frequency signals.

[0048] The present disclosure will be described in detail below in conjunction with specific embodiments.

[0049] Figure 1 The structure diagram of a microseismic sensor front-end signal conditioning circuit based on hysteresis correction frequency extension provided by the embodiments of the present disclosure.

[0050] AsFigure 1 As shown in the figure, the microseismic sensor front-end signal conditioning circuit based on lag correction frequency widening comprises:

[0051] A differential amplification circuit is configured to convert the differential signal input by the microseismic sensor into a single-ended vibration signal, pre-amplify the vibration signal according to a preset gain, and obtain an amplified vibration signal.

[0052] A filter and lag correction circuit is configured to widen the frequency range of the amplified vibration signal through filtering and lag correction, and obtain a conditioned vibration signal.

[0053] It should be noted that the magneto-electric vibration sensor will receive environmental noise that interferes with the judgment of effective signals when working in a coal mine. By connecting a differential amplification circuit in series at the output end of the sensor, such noise interference can be effectively filtered out, and effective signals can be better received.

[0054] In addition, the microseismic sensor front-end signal conditioning circuit based on lag correction frequency widening designed by using lag correction compensation and filtering principle technology can widen the lower limit of the frequency range of the vibration signal monitored by the sensor, while retaining the upper limit of the frequency range of the vibration signal monitored by the sensor to the greatest extent. By combining the filter circuit and the lag correction compensation circuit, the number of operational amplifiers can be reduced, the overall structure of the circuit can be simplified, and the influence of noise can be reduced.

[0055] Optionally, in an embodiment of the present disclosure, Figure 2 A structural schematic diagram of a microseismic sensor front-end signal conditioning circuit based on lag correction frequency widening is provided for another embodiment of the present disclosure. As shown in the figure, Figure 2 The microseismic sensor front-end signal conditioning circuit based on lag correction frequency widening further comprises:

[0056] A damping ratio correction circuit is configured to receive an initial differential signal input by the microseismic sensor, correct the initial differential signal according to a damping ratio, obtain a corrected differential signal, and input the corrected differential signal to the differential amplification circuit.

[0057] According to some embodiments, Figure 3 A structural schematic diagram of a damping ratio correction circuit and a differential amplification circuit is provided for an embodiment of the present disclosure. As shown in the figure, Figure 3 The damping ratio correction circuit comprises a first resistor R 1; wherein,

[0058] The positive output end of the microseismic sensor V in+ is connected with the first end of the first resistor R 1 and the positive input end of the differential amplification circuit, respectively. V in-a first end of the first resistor R 1 and a negative input terminal of the differential amplification circuit.

[0059] In some embodiments, the damping ratio of the corrected differential signal may satisfy the following formula:

[0060]

[0061] wherein, represents the sensitivity of the microseismic sensor, represents the inertial body mass of the microseismic sensor, represents the natural angular frequency of the microseismic sensor, represents the coil internal resistance of the microseismic sensor.

[0062] Optionally, in one embodiment of the present disclosure, as shown in Figure 3 the differential amplification circuit comprises a first operational amplifier U 1; wherein,

[0063] a positive input terminal of the first operational amplifier U 1 is connected with a positive output terminal of the microseismic sensor, a negative input terminal of the first operational amplifier U 1 is connected with a negative output terminal of the microseismic sensor, and an output terminal of the first operational amplifier U 1 is connected with an input terminal of the filter and hysteresis correction circuit.

[0064] wherein, as shown in Figure 3 the positive output terminal of the microseismic sensor V in+ is connected with a first end of the first resistor R 1 and a positive input terminal of the first operational amplifier U 1, respectively, and the negative output terminal of the microseismic sensor V in- is connected with a second end of the first resistor R 1 and a negative input terminal of the first operational amplifier U 1, respectively.

[0065] According to some embodiments, the first operational amplifier U 1 may be, for example, a programmable gain amplifier (PGA), and specifically, a programmable instrument operational amplifier. Since the conventional differential amplification circuit design needs to determine the working parameters in advance, inappropriate preset parameters may cause the loss of weak signals or the over-amplification of strong signals. By using a programmable gain amplifier in the differential amplification circuit, the gain of the differential amplification circuit can be dynamically adjusted through interaction with the control circuit.

[0066] It should be noted that the differential amplification circuit is composed of an operational amplifier, which can convert the picked-up differential signal input into single-ended output to suppress common-mode noise, and can select the gain as needed to pre-amplify the weak vibration signal, thereby improving the differential amplification effect of the differential amplification circuit.

[0067] Optionally, in one embodiment of the present disclosure, as shown in Figure 2 The filter and lag correction circuit comprises:

[0068] The high-pass filter circuit is configured to perform high-pass filtering on the amplified vibration signal to obtain a high-pass filtered vibration signal.

[0069] The first-stage lag correction circuit is configured to perform lag correction on the high-pass filtered vibration signal to obtain a lag-corrected vibration signal.

[0070] The second-stage lag correction circuit is configured to perform secondary lag correction on the lag-corrected vibration signal to obtain a secondary lag-corrected vibration signal.

[0071] The low-pass filter circuit is configured to perform low-pass filtering on the secondary lag-corrected vibration signal to obtain a conditioned vibration signal.

[0072] It should be noted that since the original magneto-electric sensor transfer function behaves as a second-order high-pass filter circuit, in order to achieve order matching and obtain better frequency extension effect, a second-stage lag correction circuit is connected in series at the output end of the first-stage lag correction circuit to form a second-order correction system, and the structure and parameters of the second-stage lag correction circuit can be consistent with those of the first-stage lag correction circuit.

[0073] In addition, the filter and lag correction circuit is provided with a high-pass filter circuit and a low-pass filter circuit, the high-pass filter circuit is used to remove the influence of DC bias and temperature drift, and the low-pass filter circuit is used to eliminate the pseudo-peak and signal aliasing caused by high-frequency interference.

[0074] The traditional method uses multiple operational amplifiers and additional capacitor and resistor elements in the circuit, thereby increasing the interference of electronic noise. The present embodiment proposes a scheme of combining the high-pass filter circuit, the low-pass filter circuit, and the lag correction circuit, and the filter circuit is cascaded with the lag correction circuit in the entire signal conditioning link, that is, the high-pass filter circuit is connected in series at the input end of the first-stage lag correction compensation circuit, and the low-pass filter circuit is connected in parallel in the feedback link of the second-stage lag correction compensation circuit, to realize high-pass and low-pass filtering, so that the circuit has lag correction and high / low-pass filtering characteristics, simplifies the circuit structure while ensuring frequency extension performance, and reduces the noise generated by electronic elements such as multiple operational amplifiers.

[0075] According to some embodiments, Figure 4 This is a schematic diagram of a filtering and hysteresis correction circuit provided in an embodiment of this disclosure. Figure 4 As shown, the high-pass filter circuit includes a first capacitor. C 1; among which,

[0076] First capacitor C The first terminal of 1 is connected to the output terminal of the differential amplifier circuit, and the first capacitor... C The second terminal of 1 is connected to the input terminal of the first-stage hysteresis correction circuit.

[0077] Among them, the first capacitor C The first terminal of 1 is connected to the first operational amplifier. U Connect the output terminal of 1.

[0078] According to some embodiments, such as Figure 4 As shown, the first-stage hysteresis correction circuit includes a second capacitor. C 2. Second resistor R 2. Third resistor R 3. Fourth resistor R 4. Fifth resistor R 5. Sixth resistor R 6. Second operational amplifier U 2; among which,

[0079] Second resistor R The first terminal of capacitor 2 is connected to the output terminal of the high-pass filter circuit, and the second capacitor... C 2 and the third resistor R The three resistors are connected in series to form the first series branch, and the second resistor... R The second terminal of 2 is connected to the second operational amplifier. U The negative input terminal of 2, the first terminal of the first series branch, and the fourth resistor R The first terminal of 4 is connected to the fourth resistor. R The second terminal of 4 is connected to the fifth resistor. R The first terminal of 5 and the sixth resistor R The first terminal of 6 is connected to the second terminal of the first series branch and the fifth resistor. R The second terminal of 5 and the second operational amplifier U The connection point between the output terminals of 2 is connected to the input terminal of the second-stage hysteresis correction circuit; the second operational amplifier U 2's positive input terminal and the sixth resistor R The second terminal of 6 is grounded.

[0080] Among them, the second resistor R The first terminal of 2 is connected to the first capacitor. C The second end of 1 is connected to the second resistor. R The second terminal of 2 is connected to the second operational amplifier.U the negative input terminal of the second capacitor C the first terminal of the second resistor R the first terminal of the fourth resistor C the second terminal of the second capacitor R the first terminal of the third resistor R the second terminal of the third resistor R the second terminal of the second operational amplifier U the connection point between the output terminal of the second capacitor

[0081] According to some embodiments, as Figure 4 shown, the second-stage lag correction circuit comprises a third capacitor C 3, a seventh resistor R 7, an eighth resistor R 8, a ninth resistor R 9, and a tenth resistor R 10 , an eleventh resistor R 11 , and a third operational amplifier U 3; wherein,

[0082] the first terminal of the seventh resistor R 7 is connected to the output terminal of the first-stage lag correction circuit, and the third capacitor C 3 is connected in series with the eighth resistor R 8 to form a second series branch, and the second terminal of the seventh resistor R 7 is connected to the negative input terminal of the third operational amplifier U 3, the first terminal of the second series branch, the first terminal of the ninth resistor R 9, and the first terminal of the low-pass filter circuit, respectively, and the second terminal of the ninth resistor R 9 is connected to the first terminal of the tenth resistor R 10 , and the first terminal of the eleventh resistor R 11 , respectively, and the second terminal of the second series branch, the second terminal of the tenth resistor R 10 , and the output terminal of the third operational amplifier U 3 are connected to the second terminal of the low-pass filter circuit, and the connection point between the positive input terminal of the third operational amplifier U 3 and the first terminal of the eleventh resistor R 11 is grounded.

[0083] wherein the second terminal of the third resistor R 3, the fifth resistor Rthe second end of 5 and the first end of the second operational amplifier U the connection point between the output of 2 and the seventh resistor R the first end of 7 is connected to the seventh resistor R the second end of 7 is connected to the third operational amplifier U the negative input of 3, the third capacitor C the first end of 3, the ninth resistor R the first end of 9 and the first end of the low pass filter circuit are connected to the third capacitor C the second end of 3 is connected to the eighth resistor R the first end of 8 is connected to the eighth resistor R the second end of 8, the tenth resistor R 10 the second end of 2, the third operational amplifier U the connection point between the output of 3 and the second end of the low pass filter circuit is the output of the filter and hysteresis correction circuit.

[0084] According to some embodiments, the low pass filter circuit comprises a fourth capacitor C 4; wherein

[0085] the fourth capacitor C the first end of 4 is connected to the seventh resistor R the second end of 7, the third operational amplifier U the negative input of 3, the first end of the second series branch and the ninth resistor R the first end of 9 is connected to the second end of the second series branch, the tenth resistor R 10 the second end of 2, the third operational amplifier U the output of 3 and the second end of the fourth capacitor C the connection point between the second end of 4 is the output of the filter and hysteresis correction circuit.

[0086] wherein the seventh resistor R the second end of 7 is connected to the third operational amplifier U the negative input of 3, the third capacitor C the first end of 3, the ninth resistor R the first end of 9 and the fourth capacitor C the first end of 3 is connected to the third capacitor C the second end of 3 is connected to the eighth resistor R the first end of 8 is connected to the eighth resistor R the second end of 8, the tenth resistor R 10 the second end of 2, the third operational amplifier U the output of 3 and the second end of the fourth capacitor C the connection point between the second end of 4 is the output of the filter and hysteresis correction circuit.

[0087] It should be noted that the hysteresis correction compensation link in the hysteresis correction circuit is composed of a plurality of resistors and a capacitor, wherein the fourth resistor R4 in the first-stage hysteresis correction circuit R 4, the fifth resistor R5 R 5, the sixth resistor R6 R 6, the ninth resistor R9 in the second-stage hysteresis correction circuit R 9, the tenth resistor R10 R 10 , the eleventh resistor R11 R 11 All can constitute a T-shaped resistor network for replacing the use of a large resistor, and the T-shaped resistor network can eliminate the signal distortion problem caused by the mismatch between the large resistor and the small capacitor. The asymmetric structure can make the total equivalent resistance value smaller than the original large resistance value, optimize the noise, power consumption and other parameters under the premise of not affecting the overall circuit network performance and maintaining the original frequency expansion performance, and reduce the influence of the problems such as low-frequency signal distortion caused by high cost, high noise, high power consumption and temperature drift of the large resistor and the symmetric network.

[0088] For example, the equivalent relationship of the T-shaped resistor network of the first-stage hysteresis correction circuit satisfies:

[0089]

[0090] At this time, the transfer function of the first-stage hysteresis correction circuit satisfies:

[0091]

[0092] wherein, is the equivalent resistance of the T-shaped resistor network, is the input voltage of the first-stage hysteresis correction circuit, is the output voltage of the first-stage hysteresis correction circuit. s is the Laplace operator.

[0093] At this time, the first-stage hysteresis correction circuit has two cutoff corner frequencies, which are respectively:

[0094]

[0095]

[0096] wherein, is the first cutoff corner frequency, is the second cutoff corner frequency.

[0097] Optionally, in an embodiment of the present disclosure, as shown in Figure 2 the hysteresis correction frequency expansion-based microseismic sensor front-end signal conditioning circuit further comprises:

[0098] The control circuit is used to adjust the preset gain in the differential amplifier circuit;

[0099] The control circuit is also used to adjust the filtering parameters and hysteresis correction parameters in the filtering and hysteresis correction circuit, so that the filtering and hysteresis correction circuit can broaden the frequency range of the amplified vibration signal to the preset frequency range corresponding to the filtering parameters and hysteresis correction parameters, thereby obtaining the conditioned vibration signal.

[0100] According to some embodiments, the control circuit may, for example, employ a microcontroller unit (MCU).

[0101] In some embodiments, such as Figure 2 As shown, in order to adapt to magnetoelectric sensors with different damping ratios, natural frequencies, and sensitivity parameters, the differential amplifier circuit, damping ratio correction circuit, and filtering and hysteresis correction circuit can be integrated into the same data acquisition board. The signal picked up by the sensor is directly processed by the data acquisition board and then output to the data acquisition system. This is equivalent to the data acquisition board being connected in series at the output end of the sensor, and the parameters can be adjusted using the control circuit.

[0102] Among them, the first operational amplifier in the differential amplifier circuit U 1. By selecting a PGA and connecting it to an MCU, the overall signal gain can be dynamically adjusted by programming the PGA gain through the SPI protocol. At the same time, in order to avoid the loss of weak signals and the over-amplification of strong signals, the MCU can control the signal gain within a reasonable range by setting a threshold, so as to realize the dynamic adjustment of the interaction between the MCU and the PGA.

[0103] In the filtering and hysteresis correction circuit, the capacitor can be a liquid crystal capacitor (LCV). The control terminal of the LCV can be connected to the output terminal of the digital-to-analog converter (DAC). The input terminal of the DAC is connected to the MCU. The MCU sends the digital signal corresponding to the capacitance value to the DAC via the SPI protocol. The DAC converts it into an analog voltage and applies it to the control terminal of the LCV to adjust the capacitance value of the LCV.

[0104] In the micro-vibration sensor front-end signal conditioning circuit based on hysteresis correction frequency extension, the resistor can be a digital potentiometer (DP), which is directly connected to the MCU. Relying on the SPI protocol, the change of the DP's resistance value can be controlled by programming.

[0105] Therefore, the advantages of analog circuits and digital circuits can be combined, MCU, PGA, LCA, and DP, and other numerical control electronic components are used to replace part of the analog components, the circuit components and working parameters are adjustable, the problem that the pure analog circuit cannot adapt to the different working parameters of the magneto-vibration sensor is solved, and a high-precision front-end vibration signal data source is provided for subsequent seismic source positioning, energy calculation, stress inversion, and the like.

[0106] It should be noted that in the case where the structure and parameters of the second-order lag correction circuit are consistent with the structure and parameters of the first-order lag correction circuit, the new natural angular frequency of the sensor after compensation can be obtained by simultaneously solving the sensor and the second-order lag correction system transfer function and according to the definition of the cutoff frequency satisfies:

[0107]

[0108] wherein, and the damping ratio correction circuit of the previous stage makes and finally obtains:

[0109]

[0110] According to the above related calculation formulas of the filter and lag correction circuit, the circuit component parameters can be determined according to the frequency extension target and the original natural angular frequency of the sensor The circuit component parameters include but are not limited to filter parameters, lag correction parameters, and the like.

[0111] wherein, for the lag correction parameters, the capacitance value and the resistance value are as appropriate as possible, and In addition, in order to reduce the resistance value of the large resistance and thus meet the requirements of low noise and low power consumption, the T-type resistance network can be designed as an asymmetric structure, and .

[0112] In some embodiments, Figure 5 is a second-order lag correction system amplitude-frequency characteristic curve diagram provided by the embodiments of the present disclosure. As Figure 5 shown, in the low-frequency band, the circuit gain of the filter and lag correction circuit is a certain value; in the high-frequency band, the circuit gain of the filter and lag correction circuit attenuates; and in the high-frequency band, the circuit gain of the filter and lag correction circuit is a certain value after attenuation.

[0113] wherein, for the filter parameters, the filter circuit should have the characteristics of not affecting the frequency extension effect while eliminating the negative effects, and thus the high-pass cutoff frequency and the low-pass cutoff frequency used by the high-pass filter circuit and the low-pass filter circuit respectively satisfy: At the same time, the maximum gain is kept at 1.

[0114] In some embodiments, Figure 6 This is a schematic diagram of the amplitude-frequency response curve of the front-end signal conditioning circuit of the micro-vibration sensor based on hysteresis correction frequency extension provided in an embodiment of this disclosure. Figure 6 As shown, At that time, the circuit still provides a high gain. At that time, the circuit began to show obvious attenuation.

[0115] It should be noted that traditional frequency extension circuit design relies entirely on analog or digital circuits. Each approach has its advantages and disadvantages, and the strengths of one can compensate for the weaknesses of the other. Therefore, this embodiment combines analog and digital circuits by employing a control circuit. This control circuit allows for adjustable circuit component parameters, adapting to detector units with different natural frequencies and initial damping ratios. Simultaneously, it leverages the low-noise advantage of digital potentiometers to improve frequency extension accuracy.

[0116] Taking one scenario as an example, a widely used magnetoelectric vibration sensor with a natural frequency of 4.5Hz was selected for verification, characterized by its wide monitoring frequency range. The normalized amplitude-frequency characteristic curve of the vibration sensor is compared with the amplitude-frequency characteristic curve of the micro-vibration sensor front-end signal conditioning circuit based on hysteresis correction frequency extension provided in this embodiment of the present disclosure, which is frequency-extended and normalized as follows: Figure 7 As shown, the cutoff frequency (gain of -3dB) of the magnetoelectric vibration sensor after signal conditioning and frequency extension is 0.1Hz. Compared to the original vibration sensor, the amplitude-frequency characteristic curve of the frequency extension sensor shifts to the left overall, indicating that the micro-vibration sensor front-end signal conditioning circuit based on hysteresis correction frequency extension provided in this embodiment significantly improves the magnetoelectric vibration sensor's ability to pick up low-frequency signals. Furthermore, the sensor maintains a relatively stable gain in the mid-to-high frequency range (4.5-600Hz) after frequency extension, indicating that the micro-vibration sensor front-end signal conditioning circuit based on hysteresis correction frequency extension provided in this embodiment preserves the magnetoelectric vibration sensor's good response to mid-to-high frequency signals as much as possible, and the frequency extension is effective.

[0117] Optionally, in one embodiment of this disclosure, multiple micro-vibration sensor front-end signal conditioning circuits with different parameters based on hysteresis correction and frequency extension can be designed in advance. The output terminals of multiple magnetoelectric vibration sensors with different parameters are directly connected in series with their corresponding micro-vibration sensor front-end signal conditioning circuits based on hysteresis correction and frequency extension to form a new vibration sensor. Then, an explosion-proof housing is installed, and a range-adjustable switch is set on the housing to realize the parameter adjustment of the micro-vibration sensor front-end signal conditioning circuit based on hysteresis correction and frequency extension.

[0118] In summary, the microseismic sensor front-end signal conditioning circuit based on the hysteresis correction frequency expansion provided by the embodiments of the present disclosure considers the advantages and disadvantages of the relatively mature low-frequency compensation technology, relies on the design principle of the hysteresis correction filter circuit, improves the pickup capability of the sensor for low-frequency signals under the premise of fixed damping ratio, without reducing the sensitivity of the sensor and sacrificing the high-frequency characteristics of the sensor to the minimum extent, and under the premise of not sacrificing the mid-high frequency response as much as possible, in combination with the vibration signal frequency monitoring range requirement of the vibration monitoring system used in the current coal mine site, has the advantages of easy implementation, economic benefits and the like.

[0119] Secondly, the signal conditioning circuit element controlled by the control circuit has the function of adjustable parameters, and self-adaptive adjustment is performed according to different parameters of the magneto-electric vibration sensor and monitoring requirements, so that the same type of signal conditioning circuit is adapted to different types of magneto-electric vibration sensors and different types and frequency ranges of monitoring requirements.

[0120] In addition, the number of operational amplifiers in the circuit and the use of large resistors are reduced, the high noise problem introduced by the cascade structure and the large number of operational amplifiers and large resistors is solved, and the circuit cost and power consumption are reduced.

[0121] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative description of the above terms can be directed to different embodiments or examples. Moreover, the described specific features, structures, materials or characteristics can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0122] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one feature. In the description of the present disclosure, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0123] Although the embodiments of the present disclosure have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the present disclosure, and the scope of the present disclosure is defined by the claims and their equivalents.

Claims

1. A microseismic sensor front-end signal conditioning circuit based on a lag correction frequency expansion, characterized in that, The circuit comprises: a differential amplification circuit for converting a differential signal input by a microseismic sensor into a single-ended vibration signal, pre-amplifying the vibration signal according to a preset gain, and obtaining an amplified vibration signal; a filter and lag correction circuit for widening a frequency range of the amplified vibration signal through filtering and lag correction, and obtaining a conditioned vibration signal, wherein the filter and lag correction circuit comprises: a high-pass filter circuit for performing high-pass filtering on the amplified vibration signal, and obtaining a high-pass filtered vibration signal; a first-stage lag correction circuit for performing lag correction on the high-pass filtered vibration signal, and obtaining a lag-corrected vibration signal, the first-stage lag correction circuit comprising a second capacitor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a second operational amplifier; wherein a first end of the second resistor is connected to an output end of the high-pass filter circuit, the second capacitor and the third resistor are connected in series to form a first series branch, a second end of the second resistor is connected to a negative input end of the second operational amplifier, a first end of the first series branch, and a first end of the fourth resistor respectively, a second end of the fourth resistor is connected to a first end of the fifth resistor and a first end of the sixth resistor respectively, and a connection point between a second end of the first series branch, a second end of the fifth resistor, and an output end of the second operational amplifier is connected to an input end of a second-stage lag correction circuit; and a positive input end of the second operational amplifier and a second end of the sixth resistor are grounded; a second-stage lag correction circuit for performing secondary lag correction on the lag-corrected vibration signal, and obtaining a secondary lag-corrected vibration signal; a low-pass filter circuit for performing low-pass filtering on the secondary lag-corrected vibration signal, and obtaining the conditioned vibration signal.

2. The circuit of claim 1, wherein, The circuit further comprises: a damping ratio correction circuit for receiving an initial differential signal input by a microseismic sensor, performing damping ratio correction on the initial differential signal, obtaining a corrected differential signal, and inputting the corrected differential signal to the differential amplification circuit.

3. The circuit of claim 2, wherein, The damping ratio correction circuit comprises a first resistor; wherein a positive output end of the microseismic sensor is connected to a first end of the first resistor and a positive input end of the differential amplification circuit respectively, and a negative output end of the microseismic sensor is connected to a second end of the first resistor and a negative input end of the differential amplification circuit respectively.

4. The circuit of claim 1, wherein, The differential amplification circuit comprises a first operational amplifier; wherein a positive input end of the first operational amplifier is connected to a positive output end of the microseismic sensor, a negative input end of the first operational amplifier is connected to a negative output end of the microseismic sensor, and an output end of the first operational amplifier is connected to an input end of the filter and lag correction circuit.

5. The circuit of claim 1, wherein, The high-pass filter circuit comprises a first capacitor; wherein a first end of the first capacitor is connected to an output end of the differential amplification circuit, and a second end of the first capacitor is connected to an input end of the first-stage lag correction circuit.

6. The circuit of claim 1, wherein, The second stage lag correction circuit comprises a third capacitor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor and a third operational amplifier. The first end of the seventh resistor is connected with the output end of the first stage lag correction circuit, the third capacitor and the eighth resistor are connected in series to form a second series branch, the second end of the seventh resistor is connected with the negative input end of the third operational amplifier, the first end of the second series branch, the first end of the ninth resistor and the first end of the low-pass filter circuit respectively, the second end of the ninth resistor is connected with the first end of the tenth resistor and the first end of the eleventh resistor respectively, and the connection point between the second end of the second series branch, the second end of the tenth resistor, the output end of the third operational amplifier and the second end of the low-pass filter circuit is the output end of the filter and lag correction circuit; the positive input end of the third operational amplifier and the second end of the eleventh resistor are grounded.

7. The circuit of claim 6, wherein, The low-pass filter circuit comprises a fourth capacitor. The first end of the fourth capacitor is connected with the second end of the seventh resistor, the negative input end of the third operational amplifier, the first end of the second series branch and the first end of the ninth resistor respectively, and the connection point between the second end of the second series branch, the second end of the tenth resistor, the output end of the third operational amplifier and the second end of the fourth capacitor is the output end of the filter and lag correction circuit.

8. The circuit of claim 1, wherein, The circuit further comprises: a control circuit configured to adjust the preset gain in the differential amplification circuit; The control circuit is further configured to adjust the filter parameter and the lag correction parameter in the filter and lag correction circuit, so that the filter and lag correction circuit widens the frequency range of the amplified vibration signal to a preset frequency range corresponding to the filter parameter and the lag correction parameter, to obtain a conditioned vibration signal.

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