Signal conditioning circuit and water supply network leakage monitoring system

Abstract

The invention relates to the technical field of pipeline sealing monitoring, and relates to a signal conditioning circuit and a water supply pipe network leakage monitoring system, the signal conditioning circuit comprises an impedance matching module, a first charge amplifier and a frequency clamping module which are connected in sequence; the impedance matching module is in communication connection with a sensor used for collecting acoustic vibration signals of the water supply network; the input end of the impedance matching module is used for receiving an acoustic vibration signal; the frequency clamping module is used for limiting the amplitude of an interference sound wave signal; the interference sound wave signal is a sound wave signal beyond a frequency range corresponding to the acoustic vibration signal sent by a water supply network; according to the invention, acoustic vibration signals collected by the sensor can be filtered, amplified and subjected to frequency limiting processing, and the influence of interference acoustic signals on a water supply network leakage detection result is reduced.

Description

Technical Field

[0001] This application relates to the field of pipeline sealing monitoring technology, and in particular to a signal conditioning circuit and a water supply network leakage monitoring system. Background Technology

[0002] With the development of Chinese cities, a large influx of people has provided a continuous driving force for industrialization, informatization, intelligentization, urban development, and social progress. At the same time, it has placed higher demands on urban infrastructure. Urban water demand has seen exponential growth, leading to a continuous expansion of water supply networks.

[0003] However, water supply networks are typically buried deep underground in cities, and current technology relies on manual physical detection of leak points. Furthermore, the deep burial of these networks, often laid beneath roads, coupled with the complexity of the underground environment and surface traffic restrictions, can significantly prolong leak response times, exacerbating water waste and operational risks.

[0004] Currently, although sensors are used to collect acoustic vibration signals from water supply networks and determine the presence of leaks based on the intensity of these signals, in reality, the acoustic vibration data detected by sensors is often affected by external environmental interference. This includes vibrations from vehicles on the road, machine noise, and other on-site sounds and mechanical vibrations. These external environmental interference signals are also collected by the sensors and uploaded to a server. These non-leakage sound waves or vibrations can interfere with the detection of leaks in the water supply network, frequently leading to false alarms. Summary of the Invention

[0005] This application aims to at least solve the technical problems existing in the prior art and provide a signal conditioning circuit and a water supply network leakage monitoring system.

[0006] In a first aspect, this application provides a signal conditioning circuit, comprising an impedance matching module, a first charge amplifier, and a frequency clamping module connected in sequence; The impedance matching module is communicatively connected to the sensor used to collect acoustic vibration signals from the water supply network. The input terminal of the impedance matching module is used to receive acoustic vibration signals, the output terminal of the impedance matching module is connected to the non-inverting input terminal of the first charge amplifier, the inverting input terminal of the first charge amplifier is used to receive reference voltage signals, and the output terminal of the first charge amplifier is connected to the input terminal of the frequency clamping module. The frequency clamping module is used to limit the amplitude of the interfering acoustic signal, which is an acoustic signal outside the frequency range corresponding to the acoustic vibration signal emitted by the water supply network. A first resistor is connected between the non-inverting input terminal and the output terminal of the first charge amplifier, and a first capacitor is connected between the non-inverting input terminal and the output terminal of the first charge amplifier. The first resistor and the first capacitor are connected in parallel.

[0007] By adopting the above technical solutions, the impedance matching module can filter the acquired acoustic vibration signal, suppress high-frequency noise in the input acoustic vibration signal, and avoid the impact of high-frequency interference on the performance of the first charge amplifier; the first charge amplifier can amplify the weak acoustic vibration signal, and the first resistor between the non-inverting input terminal and the output terminal of the first charge amplifier constitutes a DC negative feedback circuit, which can ensure the circuit gain and prevent circuit self-oscillation; the first capacitor between the non-inverting input terminal and the output terminal of the first charge amplifier constitutes a high-frequency feedback circuit, which can suppress the high-frequency howling of the circuit and achieve the purpose of beautifying and smoothing the acoustic vibration signal; the frequency clamping module can limit the amplitude of the interfering sound wave signal, and the signal conditioning circuit can identify and filter out the interfering sound wave signal in the acoustic vibration signal acquired by the sensor, reduce the influence of external interfering sound wave signal on the leakage measurement results, and improve the accuracy of the leakage detection results of the water supply network.

[0008] Optionally, the impedance matching module includes a second resistor, a third resistor, and a second capacitor, with the second resistor connected in series between the signal output terminal of the sensor and the non-inverting input terminal of the first charge amplifier; One end of the third resistor is connected between the signal output terminal of the sensor and the second resistor, and the other end of the third resistor is grounded. One end of the second capacitor is connected between the signal output terminal of the sensor and the second resistor, and the other end of the second capacitor is grounded.

[0009] By adopting the above technical solution, the specific content of the impedance matching module is clarified. The impedance matching module can filter the acoustic vibration signal collected by the sensor, suppress noise in the input acoustic vibration signal, and reduce high-frequency interference.

[0010] Optionally, the frequency clamping module includes a second charge amplifier, a fourth resistor, a fifth resistor, a third capacitor, a fourth capacitor, and a fifth capacitor. The inverting input terminal of the second charge amplifier is connected to the output terminal of the first charge amplifier, and the fourth and fifth resistors are connected in series between the inverting input terminal of the second charge amplifier and the output terminal of the first charge amplifier. The non-inverting input terminal of the second charge amplifier is connected to the output terminal of the second charge amplifier; One end of the third capacitor is connected to the output of the second charge amplifier, and the other end of the third capacitor is connected between the fourth and fifth resistors. One end of the fourth capacitor is connected to the output terminal of the second charge amplifier, and the other end of the fourth capacitor is connected between the fifth resistor and the inverting input terminal of the second charge amplifier. One end of the fifth capacitor is connected between the fifth resistor and the inverting input of the second charge amplifier, and the other end of the fifth capacitor is grounded.

[0011] By adopting the above technical solution, the specific circuit structure of the frequency clamping module was clarified.

[0012] Optionally, the output of the second charge amplifier is connected to an analog-to-digital converter (ADC). The ADC is used to convert the acoustic vibration signal processed by the frequency clamping module into a digital signal. The signal output of the ADC is communicatively connected to the signal input of the IoT module.

[0013] Optionally, a sixth resistor is connected in series between the output of the second charge amplifier and the analog-to-digital converter, and a sixth capacitor is connected between the sixth resistor and the analog-to-digital converter; one end of the sixth capacitor is connected between the sixth resistor and the analog-to-digital converter, and the other end of the sixth capacitor is grounded.

[0014] By adopting the above technical solution, the acoustic vibration signal collected by the sensor is processed by this signal conditioning circuit and coupled to the analog-to-digital sensor through the sixth resistor. The acoustic vibration signal is then uploaded to the processor through the analog-to-digital sensor for digital processing.

[0015] Optionally, the frequency clamping module (3) retains the frequency range of the acoustic vibration signal from 800Hz to 2500Hz.

[0016] By adopting the above technical solution, the frequency range specifically for abnormal vibration signals of water supply networks is limited, making the frequency clamping module more suitable for measuring leaks in water supply networks.

[0017] Secondly, the water supply network leakage monitoring system provided in this application includes: At least two sensors are placed at different locations in the water supply network, and the sensors are used to collect acoustic vibration signals. The signal conditioning circuit described above has its signal input terminal connected to the signal output terminal of the sensor for preprocessing the acoustic vibration signal to obtain the preprocessed acoustic vibration signal. The timing module is used to acquire the reception time of acoustic vibration signals; The IoT module, signal conditioning circuit, and timing module are all connected to the IoT module. The IoT module is used to receive the pre-processed acoustic vibration signal and the reception time of the acoustic vibration signal and upload them to the cloud server. It also receives the vibration source location information calculated by the cloud server based on the pre-processed acoustic vibration signal and the reception time of the acoustic vibration signal.

[0018] By adopting the above technical solution, the sensor can collect acoustic vibration signals to monitor the vibration characteristics inside the water supply network in real time; the signal conditioning circuit can preprocess the acoustic vibration signals to obtain preprocessed acoustic vibration signals; the timing module can collect the reception time of the acoustic vibration signals. After receiving the acoustic vibration signals and their corresponding reception times, the IoT module sends the acoustic vibration signals and their corresponding reception times to the processor (e.g., MCU or cloud server) for the monitor to view or access; after receiving the acoustic vibration signals and their corresponding reception times from the two sensors, the MCU or cloud server uses the acoustic vibration signals and their corresponding reception times from the two sensors to calculate the vibration source location information of the abnormal vibration; the IoT module can receive the vibration source location information calculated by the processor to obtain the accurate location of the leak point in the water supply network.

[0019] Optionally, the timing module uses a BeiDou timing device. The first signal input terminal of the BeiDou timing device is used to receive acoustic vibration signals, the second signal input terminal of the BeiDou timing device is used to receive BeiDou satellite signals, and the signal output terminal of the BeiDou timing device is communicatively connected to the signal input terminal of the IoT module.

[0020] By adopting the above technical solution, the precise timing signal of the Beidou navigation system can be extracted through the Beidou navigation antenna, making the reception time of the collected acoustic vibration signal more accurate, thereby improving the accuracy of the prediction results of the vibration source location information.

[0021] In summary, this application includes the following beneficial technical effects: The impedance matching module filters the acquired acoustic vibration signal, suppressing high-frequency noise and preventing high-frequency interference from affecting the performance of the first charge amplifier. The first charge amplifier amplifies weak acoustic vibration signals. The first resistor between the non-inverting input and output of the first charge amplifier forms a DC negative feedback circuit, ensuring circuit gain and preventing circuit self-oscillation. The first capacitor between the non-inverting input and output of the first charge amplifier forms a high-frequency feedback circuit, suppressing high-frequency howling and smoothing the acoustic vibration signal. The frequency clamping module limits the amplitude of interfering acoustic signals, and the signal conditioning circuit identifies and filters out interfering acoustic signals in the acoustic vibration signal acquired by the sensor, reducing the impact of external interference signals on leakage measurement results and improving the accuracy of water supply network leakage detection results. Attached Figure Description

[0022] Figure 1A circuit diagram of a signal conditioning circuit provided in an embodiment of this application; Figure 2 This is a schematic diagram of a water supply network leakage monitoring system provided in an embodiment of this application; Figure 3 A circuit diagram of a timing module provided in an embodiment of this application; Figure 4 This is a circuit diagram of an IoT module provided in one embodiment of this application.

[0023] Reference numerals in the attached diagram: 1. Impedance matching module; 11. Second resistor; 12. Third resistor; 13. Second capacitor; 2. First charge amplifier; 3. Frequency clamping module; 31. Second charge amplifier; 32. Fourth resistor; 33. Fifth resistor; 34. Third capacitor; 35. Fourth capacitor; 36. Fifth capacitor; 37. Sixth resistor; 38. Sixth capacitor; 4. First resistor; 5. First capacitor.

[0024] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0025] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0026] In the description of this application, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0027] In the description of this application, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0028] Acoustic vibration method is one of the methods for detecting pipeline leaks. It utilizes the characteristics of sound vibration to detect leaks in pipelines. The basic principle is as follows: Due to the water pressure in the water supply pipe, when a leak occurs at a certain point in the water supply network, the pressure at the pipe opening causes water to spray outwards. This water vibrates against the crack in the pipe opening, generating impact noise. This noise propagates along the pipe to both sides. The location of the leak is determined by capturing and analyzing the sound and / or vibration signals generated by the leak. However, the acoustic vibration data of the water supply network detected by sensors is often affected by external environmental interference, such as vibrations from vehicles on the road, machine noise, and other on-site sounds and mechanical vibrations. These external environmental interference vibration signals are also collected by the sensors and uploaded to a server. These non-pipeline leak sound waves or vibrations are unwanted. To filter out the useless parts of the acoustic vibration signals collected by the sensors and thus improve the accuracy of leak detection results, this application provides a signal conditioning circuit and a water supply network leak monitoring system.

[0029] Example 1 Reference Figure 1 This is a schematic diagram of a signal conditioning circuit provided in an embodiment of this application. The signal conditioning circuit includes an impedance matching module 1, a first charge amplifier 2, and a frequency clamping module 3 connected in sequence, wherein: The signal input terminal of the impedance matching module 1 is communicatively connected to the signal output terminal of the sensor. In this embodiment, the sensor is used to collect acoustic vibration signals of the water supply network. The input terminal of the impedance matching module 1 is used to receive the acoustic vibration signals. The output terminal of the impedance matching module 1 is connected to the non-inverting input terminal of the first charge amplifier 2. The inverting input terminal of the first charge amplifier 2 is used to receive the reference voltage signal. The output terminal of the first charge amplifier 2 is connected to the input terminal of the frequency clamping module 3.

[0030] The inverting input terminal of the first charge amplifier 2 corresponds to... Figure 1 In the REF input section, in this embodiment, the inverting input terminal (REF) of the first charge amplifier 2 receives a stable DC reference voltage signal. Its function is to provide a reference voltage for the first charge amplifier 2U1 to set the output DC level of the amplifier circuit, ensuring that the acoustic vibration signal collected by the sensor can be adapted to the input voltage range of the subsequent processing equipment after amplification and filtering, and avoiding signal distortion due to exceeding the range.

[0031] Impedance matching module 1 reduces power loss and signal reflection during acoustic vibration signal transmission, ensuring a smooth sensor output and preventing sensor self-excitation. Frequency clamping module 3 limits the amplitude of interfering acoustic signals, which are acoustic signals outside the frequency range corresponding to the acoustic vibration signals emitted by the water supply network. In this embodiment, the frequency range of the water supply network leakage signal is between 800Hz and 2500Hz. Therefore, the frequency clamping module retains acoustic vibration signals with a frequency range between 800Hz and 2500Hz. In actual operation, acoustic vibration signals with frequencies less than 800Hz and frequencies greater than 2500Hz are filtered out, thereby reducing the impact of external interference acoustic signals on the leakage measurement results.

[0032] A first resistor 4 is connected between the non-inverting input terminal and the output terminal of the first charge amplifier 2, forming a DC negative feedback circuit, which can ensure the gain of the circuit and prevent the circuit from self-oscillating.

[0033] A first capacitor 5 is connected between the non-inverting input terminal and the output terminal of the first charge amplifier 2, and a first resistor 4 is connected in parallel with the first capacitor 5; the first capacitor 5 ( Figure 1 C1 in the circuit constitutes a high-frequency feedback circuit. The function of the high-frequency feedback circuit is to suppress the high-frequency howling of the circuit and achieve the purpose of beautifying and smoothing the acoustic vibration signal.

[0034] The first charge amplifier 2 is a high-precision charge amplifier. In some examples of this embodiment, the first charge amplifier 2 uses the OPA333 model. In other examples of this embodiment, the first charge amplifier 2 can also be other models, such as the KT5854 and DFT2002, etc. This embodiment does not impose any restrictions. As the noise generated by the pipe crack propagates along the water supply network, the vibration amplitude gradually decreases. The signal conditioning circuit can amplify, limit the frequency, limit the amplitude, filter and / or reduce the noise of the weak acoustic vibration signal in the water supply network collected by the sensor, thereby reducing the impact of the interfering sound wave signal on the pipe leak screening results.

[0035] refer to Figure 1 Impedance matching module 1 includes a second resistor 11 ( Figure 1 R2 in the middle), the third resistor 12 ( Figure 1 R3 in the middle) and the second capacitor 13 ( Figure 1 (C5 in the middle) Figure 1 CN1 is the sensor, and the second resistor 11 is connected in series between the signal output terminal of the sensor and the non-inverting input terminal of the first charge amplifier 2 (i.e., Figure 1(between CN1 and the non-inverting input terminal of the first charge amplifier 2); one end of the third resistor 12 is connected between the signal output terminal of the sensor and the second resistor 11, and the other end of the third resistor 12 is grounded; one end of the second capacitor 13 is connected between the signal output terminal of the sensor and the second resistor 11, and the other end of the second capacitor 13 is grounded.

[0036] The third resistor 12 and the second capacitor 13 form a sensor impedance matching circuit to ensure a smooth sensor output and prevent sensor self-oscillation; the second resistor 11 is a circuit coupling resistor. The third resistor 12, through the frequency characteristics of the RC oscillation circuit, suppresses high-frequency noise in the input signal, preventing high-frequency interference from affecting the performance of the subsequent first charge amplifier 2 (operational amplifier OPA333). The second capacitor 13 blocks DC components, allowing only AC signals to pass through, preventing DC signals from interfering with subsequent circuits. At the same time, it works with the third resistor 12 to achieve low-pass filtering, suppressing high-frequency noise, and also assists in adjusting the input impedance to provide the first charge amplifier 2 with a compliant input signal, ensuring circuit stability and signal accuracy.

[0037] The frequency clamping module 3 includes a second charge amplifier 31, a fourth resistor 32, a fifth resistor 33, a third capacitor 34, a fourth capacitor 35, and a fifth capacitor 36. The frequency clamping module 3 can clamp the frequency of the interfering acoustic signal to a certain amplitude so that it does not affect the acoustic vibration signal corresponding to the leakage.

[0038] The inverting input terminal of the second charge amplifier 31 is connected to the output terminal of the first charge amplifier 2, and the fourth resistor 32 ( Figure 1 R4 in the middle) and the fifth resistor 33 ( Figure 1 R5) is connected in series between the inverting input terminal of the second charge amplifier 31 and the output terminal of the first charge amplifier 2; The non-inverting input terminal of the second charge amplifier 31 is connected to the output terminal of the second charge amplifier 31; the third capacitor 34 ( Figure 1 One end of C2 is connected to the output terminal of the second charge amplifier 31, and the other end of the third capacitor 34 is connected between the fourth resistor 32 and the fifth resistor 33; the fourth capacitor 35 ( Figure 1 One end of C3 is connected to the output terminal of the second charge amplifier 31, and the other end of the fourth capacitor 35 is connected between the fifth resistor 33 and the inverting input terminal of the second charge amplifier 31; the fifth capacitor 36 ( Figure 1 One end of the fifth capacitor 36 is connected between the fifth resistor 33 and the inverting input of the second charge amplifier 31, and the other end of the fifth capacitor 36 is grounded.

[0039] The fourth resistor 32 serves as the feedback signal load resistor and also provides a DC operating current path for the circuit, ensuring stable operation. The fifth resistor 33 is the base current bias resistor, used to adjust the base current and, together with other components, achieve circuit bias and stability. The third capacitor 34 serves as a DC blocking capacitor, preventing the input of the test instrument from affecting the DC operating point of the circuit and ensuring that the DC characteristics of the circuit are not disturbed. The fourth capacitor 35 provides a low-impedance path for the oscillation signal, enabling the transistor to operate in the "common-base amplification state," which is a key element for the circuit to achieve a specific frequency response. The fifth capacitor 36 serves as a high-frequency bypass capacitor, ensuring that the input signal is smoothly applied between the base and emitter, optimizing the signal transmission path.

[0040] The output of the second charge amplifier 31 is connected to an analog-to-digital converter. The analog-to-digital converter is used to convert the acoustic vibration signal processed by the frequency clamping module 3 into a digital signal. The signal output of the analog-to-digital converter is connected to the signal input of the IoT module.

[0041] The output of the second charge amplifier 31 and the analog-to-digital converter are connected in series with a sixth resistor 37. Figure 1 R6 in the diagram), the sixth resistor 37 is the circuit coupling resistor; the sixth capacitor 38 is connected between the sixth resistor 37 and the analog-to-digital converter. Figure 1 In this embodiment, the sixth capacitor 38 is a high-frequency filter capacitor; one end of the sixth capacitor 38 is connected between the sixth resistor 37 and the analog-to-digital converter, and the other end of the sixth capacitor 38 is grounded. The acoustic vibration signal collected by the sensor is processed by this signal conditioning circuit and coupled to the analog-to-digital sensor through the sixth resistor 37. The acoustic vibration signal is then uploaded to a processor (such as a microcontroller unit (MCU) or a cloud server) for digital processing.

[0042] Example 2 Reference Figure 2 In this embodiment, a water supply network leakage monitoring system includes: at least two sensors, a signal conditioning circuit as described in Embodiment 1, a timing module, and an IoT module, wherein: At least two sensors are placed at different locations in the water supply network. The sensors are used to collect acoustic vibration signals. The signal input terminal of the signal conditioning circuit is communicatively connected to the signal output terminal of the sensor. It is used to preprocess the acoustic vibration signals to obtain preprocessed acoustic vibration signals. The timing module can collect the reception time of the acoustic vibration signals. Both the signal conditioning circuit and the timing module are communicatively connected to the IoT module. The IoT module is used to receive the preprocessed acoustic vibration signals and the reception time of the acoustic vibration signals and upload them to the cloud server. It also receives the vibration source location information calculated by the cloud server based on the preprocessed acoustic vibration signals and the reception time of the acoustic vibration signals.

[0043] The sensor can monitor the physical acoustic vibration characteristics of the pipeline network in real time, and monitor abnormal vibrations of its acoustic vibration characteristics. When the sensor detects abnormal vibration, it generates an acoustic vibration signal and uploads it to the cloud server through the IoT module. The abnormal vibration is recorded in real time. At the same time, based on the timing function of the timing module, it can simultaneously receive the acoustic vibration signal from at least two sensors. By calculating the time difference between the arrival of the abnormal vibration at the two sensors, the sound source location of the abnormal vibration is calculated, ultimately achieving the functional requirement of accurately locating the leak point of the water supply pipeline network.

[0044] In this embodiment, the sensor can be a fiber optic detector, a piezoelectric vibration sensor, an acoustic sensor, a vibration velocity sensor, and / or a capacitive vibration sensor, etc. All of the above sensors can detect the mechanical vibration generated by the water pipe. During implementation, a suitable sensor can be selected according to the geographical environment of the water supply network to collect the acoustic vibration signal generated by the water pipe leak. This embodiment does not impose any restrictions.

[0045] In a preferred embodiment of this invention, multiple sets of sensors are set up at various locations in the water supply network to monitor leakage at multiple locations in the water supply network, enabling managers to conduct comprehensive monitoring of different areas of the water supply network.

[0046] Each group of sensors consists of two sensors, named the first sensor and the second sensor respectively. In a preferred embodiment, the installation distance between the first and second sensors in the same group within the water supply network needs to be less than or equal to a pre-set reference distance. In this embodiment, the installation distance between the first and second sensors in the same group within the water supply network is set to within 0.3 kilometers. Based on the physical acoustic vibration characteristics generated when the water supply network leaks, the acoustic characteristics corresponding to the acoustic vibration signal emitted when the water supply network leaks will be rapidly attenuated in the air, but the attenuation amplitude in the pipeline network is much smaller than in the air, and it will propagate to a long distance along the extension direction of the water supply network. Experiments have shown that the propagation distance of the vibration signal in the water supply pipeline is greater than or equal to 0.3 kilometers. Installing the first and second sensors in the same group within a distance of 0.3 kilometers, and setting the distance between multiple groups of first and second sensors within a distance of 0.3 kilometers (even if the distance between sensors in the water supply network is less than 0.3 kilometers), can reduce the possibility that the first sensor / or the second sensor will not detect the vibration signal due to the long installation distance.

[0047] In addition, to improve the ease of installation of the first sensor (second sensor), the first sensor and the second sensor are installed on the part of the water supply network above ground, or on the water supply network near the shallow ground surface.

[0048] The timing module uses BeiDou timing equipment. The first signal input terminal of the BeiDou timing equipment is used to receive acoustic vibration signals, the second signal input terminal of the BeiDou timing equipment is used to receive BeiDou satellite signals, and the signal output terminal of the BeiDou timing equipment is communicatively connected to the signal input terminal of the IoT module.

[0049] The BeiDou time synchronization equipment utilizes the BeiDou navigation satellites to broadcast standard time information. It proactively provides precise time to various fields or equipment requiring accurate time, thereby meeting specific functional needs. BeiDou time synchronization accuracy can reach the order of 10 nanoseconds. Achieving such high precision time measurement requires the assistance of atomic clocks. BeiDou navigation satellites are equipped with onboard atomic clocks to ensure that the BeiDou time synchronization system has a precise time source. The navigation satellites transmit signals carrying precise standard time information and satellite position information. Receivers calculate the clock difference between themselves and the satellites to correct their local time, thus completing the time synchronization.

[0050] For users in motion, their location information is needed simultaneously with time synchronization. We know that distance equals speed multiplied by time. The speed of radio propagation (speed of light c) is known; by measuring the time it takes for the radio signal to travel from the satellite to the user, the distance between them can be determined. The BeiDou time synchronization system also features a unique two-way time synchronization mode. In this mode, the user needs to interact with the ground control station, and all information processing is completed at the control station. The user initiates a time synchronization request to the control station, which then forwards the time stamp signal to the user via satellite. The user returns the received time stamp signal along the same path, and the ground control station calculates the one-way propagation delay and sends this delay information back to the user. Two-way time synchronization reflects delay information more accurately, resulting in higher time synchronization precision.

[0051] In this embodiment, the BeiDou timing circuit corresponding to the timing module is as follows: Figure 3 As shown, this circuit extracts the precise timing signal of the Beidou navigation system through the Beidou navigation antenna. This timing signal is the key reference of the circuit in this application, ensuring that all online devices can collect sensor signals within 1 ns. The Beidou timing signal is used as the working reference of this circuit to achieve the purpose of accurate location of leaks.

[0052] refer to Figure 3 In the BeiDou timing circuit, U1 is the BeiDou navigation timing module, which obtains precise time synchronization. CN1 is the BeiDou antenna, used for precise time synchronization of devices within the network. TX2 and RX2 are data exchange channels between the timing module and the processor (MCU). 1PPS is the timing output of the BeiDou module, a rectangular wave with a width of 1 second, serving as the time reference. In the BeiDou timing circuit, FB1, FB2, FB3, FB4, FB5, and FB6 are electromagnetic compatibility devices used to suppress radio frequency interference.

[0053] The IoT module utilizes Internet of Things (IoT) technology to connect devices in different physical locations via communication methods, integrating acoustic vibration signals and their corresponding reception times. Upon receiving the acoustic vibration signals and their corresponding reception times, the IoT module sends them to a processor (such as an MCU or cloud server) for monitoring and retrieval. After receiving the acoustic vibration signals and their corresponding reception times from the two sensors, the MCU or cloud server calculates the location information of the abnormal vibration source using these signals. The IoT module can then receive the vibration source location information calculated by the processor to accurately pinpoint the location of leaks in the water supply network.

[0054] In this embodiment, the IoT circuit corresponding to the IoT module is as follows: Figure 4As shown, the function of the IoT circuit is to enable interconnection and data exchange between water supply network leakage monitoring systems.

[0055] The IoT circuit includes IoT chip CN1 and IoT chip CN2. Pins 1, 2, 3 and 4 of IoT chip CN1 are input pins. Pin 1 of IoT chip CN1 is 4G_LINK_A and pin 2 of CN1 is 4G_LINK_B. 4G_LINK_A and 4G_LINK_B are network connection-related input pins that receive signals related to network connection status and are used to monitor and obtain information such as the connection status of the 4G network.

[0056] Pin 3 of the IoT chip CN1 is connected to 4G_OTG_FS_DM, and pin 4 of the IoT chip CN1 is 4G_OTG_FS_DP. 4G_OTG_FS_DM and 4G_OTG_FS_DP are USB-related differential input signal pins that receive differential data signals transmitted from external devices via USB. They can be used to communicate with external devices via USB and realize data transmission and other functions.

[0057] 4G_RXD1 is pin 6 of the IoT chip CN1: 4G_RXD1 is the serial receive input pin of the 4G module, which receives serial data signals sent from external devices, thereby realizing serial communication with external devices.

[0058] 4G_TXD1 is pin 7 of the IoT chip CN1. 4G_TXD1 is the serial transmit output pin of the 4G module, which transmits the serial data signal generated by the 4G module to external devices.

[0059] For the IoT chip CN2: DCIN corresponds to pins 1, 2, and 3 of the IoT chip CN2. It is a DC input pin used to receive the externally supplied DC power supply voltage and provide the power required for the entire 4G IoT module and related circuits to operate. RESET corresponds to pin 7 of the IoT chip CN2, which is the reset signal input pin. It receives external reset trigger signals and can reset the 4G module to restore it to its initial state.

[0060] VSIM corresponds to pin 8 of the IoT chip CN2. It is a SIM card power-related input pin used to receive signals that provide operating voltage to the SIM card, ensuring that the SIM card can work properly to achieve functions such as identity authentication.

[0061] The SIM signal corresponds to pins 9-11 of the IoT chip CN2: pins 9-11 of the IoT chip CN2 are used to receive various data, clock and other signals from the SIM card, and are used to interact with the SIM card, such as reading user information in the SIM card.

[0062] 4G_GPIO_GF1 to 4G_GPIO_GF4 are connected to pins 8-11 of the IoT chip CN2 respectively: These are general-purpose input / output pins, which can be used as output pins to send various general-purpose control or data signals to external devices for various forms of GPIO communication to achieve customized function control, etc.

[0063] The IoT chip in the IoT module used for data exchange can be a commonly used IoT chip that is already available on the market, such as Unisoc UIS8910, Ivy 8910DM, EC618, EC716S or EC716E, etc. Alternatively, a new IoT chip can be designed according to one's own needs. This application does not impose any restrictions.

[0064] In the description of this specification, the references to terms such as "an embodiment," "some embodiments," "example," "specific example," "a implementation," "a preferred implementation," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A signal conditioning circuit, characterized in that, It includes an impedance matching module (1), a first charge amplifier (2), and a frequency clamping module (3) connected in sequence; The impedance matching module (1) is communicatively connected to the sensor used to collect acoustic vibration signals of the water supply network; The input terminal of the impedance matching module (1) is used to receive acoustic vibration signals. The output terminal of the impedance matching module (1) is connected to the non-inverting input terminal of the first charge amplifier (2). The inverting input terminal of the first charge amplifier (2) is used to receive reference voltage signals. The output terminal of the first charge amplifier (2) is connected to the input terminal of the frequency clamping module (3). The frequency clamping module (3) is used to limit the amplitude of the interfering acoustic signal. The interfering acoustic signal is an acoustic signal outside the frequency range corresponding to the acoustic vibration signal emitted by the water supply network. A first resistor (4) is connected between the non-inverting input terminal and the output terminal of the first charge amplifier (2), and a first capacitor (5) is connected between the non-inverting input terminal and the output terminal of the first charge amplifier (2). The first resistor (4) and the first capacitor (5) are connected in parallel.

2. The signal conditioning circuit as described in claim 1, characterized in that, The impedance matching module (1) includes a second resistor (11), a third resistor (12), and a second capacitor (13). The second resistor (11) is connected in series between the signal output terminal of the sensor and the non-inverting input terminal of the first charge amplifier (2). One end of the third resistor (12) is connected between the signal output terminal of the sensor and the second resistor (11), and the other end of the third resistor (12) is grounded; One end of the second capacitor (13) is connected between the signal output terminal of the sensor and the second resistor (11), and the other end of the second capacitor (13) is grounded.

3. The signal conditioning circuit as described in claim 1 or 2, characterized in that, The frequency clamping module (3) includes a second charge amplifier (31), a fourth resistor (32), a fifth resistor (33), a third capacitor (34), a fourth capacitor (35), and a fifth capacitor (36). The inverting input terminal of the second charge amplifier (31) is connected to the output terminal of the first charge amplifier (2), and the fourth resistor (32) and the fifth resistor (33) are connected in series between the inverting input terminal of the second charge amplifier (31) and the output terminal of the first charge amplifier (2). The non-inverting input terminal of the second charge amplifier (31) is connected to the output terminal of the second charge amplifier (31); One end of the third capacitor (34) is connected to the output terminal of the second charge amplifier (31), and the other end of the third capacitor (34) is connected between the fourth resistor (32) and the fifth resistor (33). One end of the fourth capacitor (35) is connected to the output terminal of the second charge amplifier (31), and the other end of the fourth capacitor (35) is connected between the fifth resistor (33) and the inverting input terminal of the second charge amplifier (31). One end of the fifth capacitor (36) is connected between the fifth resistor (33) and the inverting input of the second charge amplifier (31), and the other end of the fifth capacitor (36) is grounded.

4. The signal conditioning circuit as described in claim 3, characterized in that, The output of the second charge amplifier (31) is connected to an analog-to-digital converter. The analog-to-digital converter is used to convert the acoustic vibration signal processed by the frequency clamping module (3) into a digital signal. The signal output of the analog-to-digital converter is connected to the signal input of the IoT module.

5. The signal conditioning circuit as described in claim 4, characterized in that, The output of the second charge amplifier (31) is connected in series with the analog-to-digital converter via a sixth resistor (37), and a sixth capacitor (38) is connected between the sixth resistor (37) and the analog-to-digital converter. One end of the sixth capacitor (38) is connected between the sixth resistor (37) and the analog-to-digital converter, and the other end of the sixth capacitor (38) is grounded.

6. The signal conditioning circuit as described in claim 1, 2, 4, or 5, characterized in that, The frequency clamping module (3) retains the frequency range of the acoustic vibration signal from 800Hz to 2500Hz.

7. A water supply network leakage monitoring system, characterized in that, The system includes: At least two sensors are placed at different locations in the water supply network, and the sensors are used to collect acoustic vibration signals. The signal conditioning circuit as described in any one of claims 1 to 6, wherein the signal input terminal of the signal conditioning circuit is communicatively connected to the signal output terminal of the sensor, and is used to preprocess the acoustic vibration signal to obtain the preprocessed acoustic vibration signal; The timing module is used to acquire the reception time of acoustic vibration signals; The IoT module, signal conditioning circuit, and timing module are all connected to the IoT module. The IoT module is used to receive the pre-processed acoustic vibration signal and the reception time of the acoustic vibration signal and upload them to the cloud server. It also receives the vibration source location information calculated by the cloud server based on the pre-processed acoustic vibration signal and the reception time of the acoustic vibration signal.

8. The water supply network leakage monitoring system as described in claim 7, characterized in that, The timing module uses BeiDou timing equipment. The first signal input terminal of the BeiDou timing equipment is used to receive acoustic vibration signals, the second signal input terminal of the BeiDou timing equipment is used to receive BeiDou satellite signals, and the signal output terminal of the BeiDou timing equipment is communicatively connected to the signal input terminal of the IoT module.

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