An ultrasonic flow meter echo signal discrimination processing system and method

Abstract

This invention relates to the field of ultrasonic flow detection. Specifically, it relates to an echo signal discrimination and processing system and method. It mainly includes a threshold judgment module, a zero-point judgment module, a timing module, a peak detection module, a frequency output module, and an MCU microprocessor. It can filter echo signals. When the frequency of the echo signal input to the discrimination and processing system differs from the frequency emitted by the transmitter, it can be directly determined that it is not a valid echo signal, and the MCU microprocessor will not perform further calculations or analysis. Similarly, when the voltage ratio between the peak voltage of the first wave and the peak voltage of the maximum echo does not meet the standard, it can also be directly determined that it is not a valid echo signal. This system can perform multi-dimensional and comprehensive discrimination and processing of echo signals, allowing the microprocessor to process only valid echo signals that meet the standards. This helps reduce the power consumption of the microprocessor, saves its computing power, and significantly improves the performance of the ultrasonic flow meter.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic flow detection. Specifically, it relates to an echo signal discrimination and processing system and method. Background Technology

[0002] An ultrasonic flow meter is an instrument used to measure the velocity of fluid flow. It calculates the flow rate by utilizing the propagation speed of ultrasonic waves in a target fluid. An ultrasonic flow meter typically consists of a sensor and a processor. The sensor emits ultrasonic waves and receives the echoes, while the processor calculates the fluid velocity and flow rate based on the echo time and frequency. Ultrasonic flow meters offer advantages such as high measurement accuracy, non-invasive operation, and applicability to various media and pipe sizes, making them widely used in industrial fields, particularly for liquid and gas flow measurement.

[0003] Ultrasonic flow meters typically consist of a transmitter and a receiver. During operation, the transmitter emits an ultrasonic pulse into the fluid. This pulse propagates along the fluid, forming a sound beam. The receiver receives the echo signal and converts it into a voltage signal that can be recognized by the processing circuitry. Chinese patent document CN102322905A discloses a transducer drive circuit for an ultrasonic flow meter. This circuit increases the output voltage by controlling a BOOST boost circuit to ensure the strength of the transmitter's emitted signal. This allows the amplitude of the received signal to remain within a certain range even with large pipe diameters, reducing the design complexity of the receiver circuit gain.

[0004] The received signal amplitude mentioned in the aforementioned patent document is a crucial parameter for the processing circuit to confirm the echo signal. However, due to various interference factors such as burrs and abnormal deposits inside the metering pipe, the echo signal may experience abnormal distortion or skipping. Therefore, the processing circuit needs to combine other parameters for comprehensive discrimination processing of the received echo signal. Typically, a standard signal waveform is a series of sinusoidal envelopes with gradually increasing peak values, reaching a maximum value and then decreasing. The frequency, peak-to-peak value of the first wave, and peak-to-peak value of the maximum echo are all used as criteria for the processing circuit to determine whether the echo signal is usable. In existing technologies, microprocessors are often used to calculate all echo signals received by the receiver without selection. Consequently, processing a large number of abnormal voltage signals increases circuit power consumption and wastes computing power. Summary of the Invention

[0005] The purpose of this invention is to provide an ultrasonic flow meter echo signal discrimination and processing system. This system can discriminate and process echo signals in a multi-dimensional and comprehensive manner by comparing thresholds and zero-crossing points, combined with frequency judgment. This allows the microprocessor to process only valid echo signals that meet the standards, which helps to reduce the power consumption of the microprocessor, save its computing power, and significantly improve the performance of the ultrasonic flow meter.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An ultrasonic flow meter echo signal discrimination and processing system, characterized in that it further comprises:

[0008] A threshold judgment module receives the echo signal and compares its first wave amplitude with a set threshold, and sends the comparison result signal to the timing module.

[0009] The zero-point detection module receives the echo signal and automatically determines the zero-point position. Whenever a zero point is detected, it sends a zero-point count signal to the frequency output module.

[0010] The timing module receives the comparison result signal sent by the threshold judgment module, and simultaneously generates a time pulse signal and sends the time pulse signal to the peak detection module;

[0011] A peak detection module receives the echo signal and the time pulse signal, and sends the voltage values ​​of the first wave voltage peak and the maximum echo voltage peak to the MCU microprocessor.

[0012] A frequency output module receives the zero-point counting signal and the time pulse signal, generates frequency pulse information, and sends the frequency pulse information to the MCU microprocessor.

[0013] The MCU microprocessor determines whether the echo signal is a valid echo signal based on the frequency pulse information and the numerical information of the first wave voltage peak and the maximum echo voltage peak.

[0014] Therefore, after receiving the ultrasonic echo signal, the receiver converts it into an analog voltage echo signal, which is then sent to the threshold judgment module, the zero-point judgment module, and the peak detection module. The threshold judgment module is specifically a threshold comparator circuit. This circuit selects waves from the echo signal whose amplitude reaches a preset threshold. Specifically, when the amplitude of this wave reaches the set threshold, the threshold comparator outputs a high-level pulse signal to the timing module, i.e., the comparison result signal, used to determine the position of the first wave in the entire echo signal and start the timing operation. The zero-point judgment module mainly consists of a zero-crossing comparator and auxiliary circuitry. The zero-crossing comparator detects whether the input echo signal crosses a zero point. When a zero point is detected, it outputs a high-level zero-point count signal to the frequency output module. Each echo signal contains multiple zero points. Combined with the first wave position determined by the threshold comparator, the starting zero point corresponding to that first wave position is selected as the starting point for frequency calculation of the entire echo signal.

[0015] The timing module consists of a timer. The timer's inherent characteristics allow it to output a time pulse signal of a specific duration. The starting point of the time pulse signal is the arrival time of the comparison result signal, i.e., it is triggered by a rising edge. When a high-level pulse from the threshold comparator is input to the timer, the timer outputs a high-level pulse signal of a specific duration to the frequency output module. The frequency output module mainly consists of an AND gate, which simultaneously receives the time pulse signal and the zero-point count signal. When both signals are high-level, the AND gate outputs a high-level frequency pulse information to the MCU microprocessor. The frequency of the echo signal can be calculated by combining this duration and the zero-point position with the number of zeros in the echo signal.

[0016] The peak detection module consists of a peak sampling circuit that receives echo signals and time pulse signals. The time pulse signal is used to turn on the analog switch in the module. Then, it stores the first peak voltage and the maximum echo voltage peak to form sampling data. The sampling data is then sent to the MCU microprocessor connected to it. The MCU microprocessor has a built-in ADC digital-to-analog converter circuit, which can convert the analog voltage signal into a digital voltage signal that can be processed. The MCU microprocessor performs calculations on the data to determine the numerical ratio between the first peak voltage and the maximum echo voltage peak. When the ratio matches the preset numerical ratio in the MCU microprocessor, for example, 1:3 (±10%), it indicates that the echo signal is a valid echo signal.

[0017] When the frequency and peak value ratios of the aforementioned echo signals match the standard data, they can be identified as valid echo signals. The MCU microprocessor will then process these valid echo signals as a reference for calculating the time of flight. In this system, through the cooperation of various modules, valid echo signals can be effectively filtered out. The MCU microprocessor only needs to perform time of flight calculations based on the filtered valid echo signals, ignoring invalid echo signals caused by adverse factors. This reduces data processing pressure, saves MCU microprocessor power consumption and computing power, and improves the processing performance of the ultrasonic flow meter.

[0018] As a preferred embodiment of the present invention, the threshold determination module includes a voltage reference circuit for outputting a threshold voltage and a threshold comparator connected to the voltage reference circuit; the negative input terminal of the threshold comparator is connected to the output terminal of the voltage reference circuit, and the positive input terminal of the threshold comparator is connected to the echo signal setpoint terminal.

[0019] Therefore, the voltage reference circuit consists of a voltage reference chip and peripheral auxiliary circuits. It is connected to the negative input terminal of the threshold comparator as the basis for comparison. The magnitude of the comparison voltage can be set according to the actual characteristics of the pipeline, such as 200mV. The positive input terminal of the threshold comparator is connected to the echo signal set terminal. When the amplitude of a certain wave of the echo signal reaches 200mV, the output terminal of the threshold comparator will output a high-level signal to the timing module to instruct the timing module to start generating a time pulse signal.

[0020] As a preferred embodiment of the present invention, the timing module includes a first timer and a second timer connected in parallel, the clock input terminals of the first timer and the second timer are connected to the output terminal of the threshold comparator; a secondary trigger suppression circuit is provided between the output terminal of the second timer and the input terminal of the first timer.

[0021] The frequency of the echo signal is determined by the transmitter of a set of ultrasonic transducers. This echo signal may change frequency after being subjected to abnormal interference inside the pipe. When the frequency-changed echo signal is received by the receiver, its usability needs to be determined by the frequency output module and the MCU microprocessor. The inherent frequencies of the first and second timers determine the length of the time pulse signal generated after being triggered by a rising high-level edge. For example, the first timer generates a 5μs high-level pulse signal after being triggered by a rising high-level edge; the second timer generates a 50μs high-level pulse signal. The 50μs high-level pulse signal from the second timer, along with the high-level zero-point count signal generated by the zero-point detection module, serves as the judgment parameter for the frequency output module. For example, if nine zero-point signals are input within 50μs, the frequency can be calculated.

[0022] Since the threshold judgment module continuously outputs a high-level signal to the first timer and the second timer after the first wave passes, in order to ensure that the first timer is not repeatedly triggered during the time when the second timer outputs a high-level pulse signal, a secondary trigger suppression circuit is set between the output terminal of the second timer and the input terminal of the first timer. This secondary trigger suppression circuit consists of a core NMOS transistor and auxiliary circuits. When the high-level pulse signal output by the second timer is connected to the control terminal of the NMOS transistor, it continuously cuts off the current path between the threshold comparator and the first timer, preventing the first timer from being triggered twice and causing incorrect indications to the entire circuit.

[0023] As a preferred embodiment of the present invention, the peak detection module includes two analog switch circuits and two peak voltage storage units; the control terminals of the two analog switch circuits are respectively connected to the output terminals of the first timer and the second timer; the input terminals of the two peak voltage storage units are respectively connected to the output terminals of the two analog switch circuits; and the output terminals of the two peak voltage storage units are both connected to the data input terminal of the MCU microprocessor.

[0024] The input terminal of the peak voltage storage unit is connected to the output terminals of two analog switch circuits, and its core is a capacitor. The control terminals of the analog switch circuits are connected to the output terminals of the first timer and the second timer. When the high-level pulse signal output by the first timer is sent to an analog switch circuit connected to it, the analog switch circuit is turned on. At this time, the first wave voltage is charged into a peak voltage storage unit connected to the analog switch circuit. When the high-level pulse signal output by the first timer ends, the voltage reaches its peak value. At this time, the complete first wave peak voltage is stored, and the analog switch circuit is turned off. When the high-level pulse signal output by the second timer is sent to an analog switch circuit connected to it, the analog switch circuit is turned on. At this time, the voltage of the maximum echo is charged into a peak voltage storage unit connected to the analog switch circuit. When the high-level pulse signal output by the second timer ends, the voltage of the maximum echo reaches its peak value. At this time, the complete maximum echo peak voltage is stored, and the analog switch circuit is turned off.

[0025] Two peak voltage storage units, which store the first peak voltage and the maximum echo peak voltage respectively, are connected to the MCU microprocessor. The voltage information is sent to the MCU microprocessor, which automatically calculates the ratio. If the ratio is 1:3 (±10%), the echo signal is considered a valid echo signal.

[0026] As a preferred embodiment of the present invention, the peak detection module further includes a constant current switching circuit, the input terminal of which is connected to the given terminal of the echo signal, and the output terminal of which is connected to the input terminals of the two analog switching circuits.

[0027] The constant current switching circuit is used to receive the echo signal, which is an analog voltage echo. When the first wave voltage and the maximum echo voltage of the echo signal are charging the capacitor in the peak voltage storage unit, the constant current switching circuit can rectify the current passing through it to a constant current to ensure that the capacitor can be charged stably.

[0028] As a preferred embodiment of the present invention, each peak voltage storage unit is connected in parallel with a release unit at both ends, and the control terminal of the release unit is connected to the data output terminal of the MCU microprocessor.

[0029] The release unit is a transistor component, and its control pin is connected to a specific output pin of the MCU microprocessor. Thus, when the capacitor in the peak voltage storage unit finishes charging and sends the voltage value information to the MCU microprocessor, the MCU microprocessor sends a release command pulse to the transistor component through the specific output pin, controlling the transistor component to turn on, thereby releasing the energy in the capacitor connected in parallel with it, clearing its voltage value, and preparing for the next recharging.

[0030] As a preferred embodiment of the present invention, a buffer circuit for ensuring signal output stability is provided between the peak detection module and the MCU microprocessor.

[0031] The buffer circuit can employ two signal amplification circuits, which are respectively connected to two peak voltage storage units. When the MCU microprocessor sends the first peak voltage and the maximum echo peak voltage values, the signal is amplified by the amplification circuit, which can avoid signal distortion.

[0032] The present invention also provides a method for processing echo signals from an ultrasonic flow meter, characterized in that the method includes:

[0033] S01, the threshold judgment module and the zero-point judgment module receive the echo signal; the threshold judgment module compares the first wave amplitude of the echo signal with the size of the set threshold and generates a comparison result signal; the zero-point judgment module automatically determines the zero-point position and generates a zero-point count signal whenever a zero point is detected.

[0034] S02, the threshold judgment module sends the comparison result signal to the timing module; the zero-point judgment module sends the zero-point counting signal to the timing module; the timing module generates a time pulse signal of a specific duration;

[0035] S03. The timing module sends the time pulse signal to the peak detection module. The peak-to-peak detection module collects the voltage value information of the first wave voltage peak and the maximum echo voltage peak, and sends the voltage value information to the MCU microprocessor. The timing module sends the time pulse signal to the frequency output module. The zero-point judgment module sends the zero-point counting signal to the frequency output module. The frequency output module generates frequency pulse information and sends the frequency pulse information to the MCU microprocessor.

[0036] S04. The MCU microprocessor calculates the peak ratio based on the received voltage value information and obtains the ratio value; the MCU microprocessor obtains a discrimination result through the ratio value and the frequency information.

[0037] In summary, the present invention has the following beneficial effects:

[0038] 1. By setting a threshold judgment module, a zero-point judgment module, a timing module, a peak detection module, a frequency output module, and an MCU microprocessor, echo signals can be filtered. When the frequency of the echo signal input to the discrimination processing system is different from the frequency emitted by the transmitter, it can be directly determined that it is not a valid echo signal, and the MCU microprocessor will not perform further calculations and analyses, saving computing power. When the voltage ratio between the peak value of the first wave voltage and the peak value of the maximum echo voltage does not meet the standard, it can also be directly determined that it is not a valid echo signal.

[0039] 2. By coordinating the first and second timers, not only can the frequency of the echo signal be determined, but also a specific time pulse signal can be output to control the opening and closing states of the two analog switch circuits. This ensures that the peak voltage storage unit can accurately acquire the first peak voltage and the maximum echo peak voltage, providing a basis for subsequent analysis by the MCU microprocessor.

[0040] 3. Each peak voltage storage unit is connected in parallel with a release unit at both ends. After acquiring the voltage value information, the MCU microprocessor can control the release unit to release the capacitor energy in the peak voltage storage unit to prepare for the next charging, thus ensuring the reliability of continuous system operation. Attached Figure Description

[0041] Figure 1 This is a block diagram showing the connection of the first module of the ultrasonic flowmeter echo signal discrimination and processing system.

[0042] Figure 2 This is a block diagram showing the connection of the second module of the ultrasonic flowmeter echo signal discrimination and processing system.

[0043] Figure 3 This is a schematic diagram of the echo signal in the echo signal discrimination and processing system of this ultrasonic flowmeter. Detailed Implementation

[0044] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. Any person may implement the present disclosure in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0045] After receiving the ultrasonic echo signal, the receiver converts it into an analog voltage echo signal, which is then sent to the threshold judgment module, zero-point judgment module, and peak detection module. The threshold judgment module is specifically a threshold comparator circuit. This circuit selects waves from the echo signal whose amplitude reaches a preset threshold. Specifically, when the amplitude of this wave reaches the set threshold, the threshold comparator outputs a high-level pulse signal to the timing module, i.e., the comparison result signal, used to determine the position of the first wave in the entire echo signal and initiate the timing operation. The threshold judgment module also includes a voltage reference circuit and a threshold comparator. The voltage reference circuit consists of a voltage reference chip and peripheral auxiliary circuitry, connected to the negative input terminal of the threshold comparator as the comparison basis. The magnitude of the comparison voltage can be set according to the actual pipe characteristics, such as 200mV. The positive input terminal of the threshold comparator is connected to the echo signal setpoint. When the amplitude of a wave in the echo signal reaches 200mV, the output terminal of the threshold comparator outputs a high-level signal to the timing module, instructing the timing module to start generating a time pulse signal.

[0046] The zero-crossing detection module mainly consists of a zero-crossing comparator and auxiliary circuits. The zero-crossing comparator is used to detect whether the input echo signal crosses the zero point. When a zero point is detected, it outputs a high-level zero-crossing count signal to the frequency output module. Each echo signal contains multiple zero points. Combined with the first wave position determined by the threshold comparator, the starting zero point corresponding to the first wave position is selected as the starting point for frequency calculation of the entire echo signal.

[0047] The timing module consists of timers. The inherent characteristics of the timers determine that they can output time pulse signals of a specific length. The starting point of the time pulse signal is the arrival time of the comparison result signal, i.e., a rising edge trigger. When a high-level pulse output from the threshold comparator is input to the timer, the timer outputs a high-level pulse signal of a specific length to the frequency output module. The timing module includes a first timer and a second timer connected in parallel. The clock inputs of the first and second timers are connected to the output of the threshold comparator. A secondary trigger suppression circuit is provided between the output of the second timer and the input of the first timer. The inherent frequencies of the first and second timers determine the length of the time pulse signal generated after being triggered by a rising edge. For example, the first timer generates a high-level time pulse signal of 5μs after being triggered by a rising edge; the second timer generates a high-level time pulse signal of 50μs after being triggered by a rising edge. The 50μs high-level pulse signal of the second timer, together with the high-level zero-point count signal generated by the zero-point judgment module, will be used as the judgment parameter of the frequency output module. For example, if 9 zero-point signals are input within 50μs, the frequency can be calculated.

[0048] Since the threshold judgment module continuously outputs a high-level signal to the first timer and the second timer after the first wave passes, in order to ensure that the first timer is not repeatedly triggered during the time when the second timer outputs a high-level pulse signal, a secondary trigger suppression circuit is set between the output terminal of the second timer and the input terminal of the first timer. This secondary trigger suppression circuit consists of a core NMOS transistor and auxiliary circuits. When the high-level pulse signal output by the second timer is connected to the control terminal of the NMOS transistor, it continuously cuts off the current path between the threshold comparator and the first timer, preventing the first timer from being triggered twice and causing incorrect indications to the entire circuit.

[0049] The frequency output module mainly consists of an AND logic gate, which simultaneously receives a time pulse signal and a zero-point count signal. When both signals are high-level, the AND logic gate outputs a high-level frequency pulse information to the MCU microprocessor. The frequency of the echo signal can be calculated by combining this time length and zero-point position with the number of zeros in an echo signal.

[0050] The peak detection module consists of a peak sampling circuit that receives echo signals and time pulse signals. The time pulse signal is used to turn on the analog switch in the module. Then, it stores the first peak voltage and the maximum echo voltage peak to form sampling data. The sampling data is then sent to the MCU microprocessor connected to it. The MCU microprocessor has a built-in ADC digital-to-analog converter circuit, which can convert the analog voltage signal into a digital voltage signal that can be processed. The MCU microprocessor performs calculations on the data to determine the numerical ratio between the first peak voltage and the maximum echo voltage peak. When the ratio matches the preset numerical ratio in the MCU microprocessor, for example, 1:3 (±10%), it indicates that the echo signal is a valid echo signal. The input terminals of the peak voltage storage unit are connected to the output terminals of two analog switch circuits, with a capacitor as its core component. The control terminals of the analog switch circuits are connected to the output terminals of the first timer and the second timer. When the high-level pulse signal output by the first timer is sent to one of the analog switch circuits connected to it, the analog switch circuit opens, and the first wave voltage is charged into a peak voltage storage unit connected to that analog switch circuit. When the high-level pulse signal output by the first timer ends, the voltage reaches its peak value, and the complete first wave peak voltage is stored, at which point the analog switch circuit opens. Similarly, when the high-level pulse signal output by the second timer is sent to one of the analog switch circuits connected to it, the analog switch circuit opens, and the voltage of the maximum echo is charged into a peak voltage storage unit connected to that analog switch circuit. When the high-level pulse signal output by the second timer ends, the voltage of the maximum echo reaches its peak value, and the complete maximum echo peak voltage is stored, at which point the analog switch circuit opens. The peak detection module also includes a constant current switch circuit. The input terminal of the constant current switch circuit is connected to the given terminal of the echo signal, and the output terminal of the constant current switch circuit is connected to the input terminals of the two analog switch circuits. A constant current switching circuit is used to receive echo signals, which are analog voltage echoes. When the first and maximum echo voltages of the signal charge the capacitor in the peak voltage storage unit, the constant current switching circuit can regulate the current to a constant current, ensuring stable charging of the capacitor. Each peak voltage storage unit has a release unit connected in parallel across its terminals. The control terminal of the release unit is connected to the data output terminal of the MCU microprocessor. The release unit is a transistor component, and its control pin is connected to a specific output pin of the MCU microprocessor. Therefore, when the capacitor in the peak voltage storage unit finishes charging and sends its voltage value to the MCU microprocessor, the MCU microprocessor sends a release command pulse to the transistor component through the specific output pin, controlling the transistor component to conduct, thereby releasing the energy in the capacitor connected in parallel, clearing its voltage value, and preparing for the next recharging. A buffer circuit is provided between the peak detection module and the MCU microprocessor to ensure signal output stability.The buffer circuit can employ two signal amplification circuits, which are respectively connected to two peak voltage storage units. When the MCU microprocessor sends the first peak voltage and the maximum echo peak voltage values, the signal is amplified by the amplification circuit, which can avoid signal distortion.

[0051] When the frequency and peak value ratios of the aforementioned echo signals match the standard data, they can be identified as valid echo signals. The MCU microprocessor will then process these valid echo signals as a reference for calculating the time of flight. In this system, through the cooperation of various modules, valid echo signals can be effectively filtered out. The MCU microprocessor only needs to perform time of flight calculations based on the filtered valid echo signals, ignoring invalid echo signals caused by adverse factors. This reduces data processing pressure, saves MCU microprocessor power consumption and computing power, and improves the processing performance of the ultrasonic flow meter.

[0052] Several embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technological improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An ultrasonic flowmeter echo signal discrimination and processing system, characterized in that, Also includes: A threshold determination module receives an echo signal and compares its initial amplitude with a set threshold, then sends the comparison result signal to a timing module. The threshold determination module includes a voltage reference circuit for outputting a threshold voltage and a threshold comparator connected to the voltage reference circuit. The negative input terminal of the threshold comparator is connected to the output terminal of the voltage reference circuit, and the positive input terminal of the threshold comparator is connected to the echo signal setpoint. The zero-point detection module receives the echo signal and automatically determines the zero-point position. Whenever a zero point is detected, it sends a zero-point count signal to the frequency output module. The timing module receives a comparison result signal sent by the threshold judgment module, and simultaneously generates a time pulse signal and sends the time pulse signal to the peak detection module; the timing module includes a first timer and a second timer arranged in parallel, and the clock input terminals of the first timer and the second timer are connected to the output terminal of the threshold comparator; A peak detection module receives the echo signal and the time pulse signal, and sends the voltage values ​​of the first peak voltage and the maximum echo voltage peak to the MCU microprocessor. The peak detection module includes two analog switch circuits and two peak voltage storage units. The control terminals of the two analog switch circuits are respectively connected to the output terminals of the first timer and the second timer. The input terminals of the two peak voltage storage units are respectively connected to the output terminals of the two analog switch circuits. The output terminals of both peak voltage storage units are connected to the data input terminals of the MCU microprocessor. A frequency output module receives the zero-point counting signal and the time pulse signal, generates frequency pulse information, and sends the frequency pulse information to the MCU microprocessor. The MCU microprocessor determines whether the echo signal is a valid echo signal based on the frequency pulse information and the numerical information of the first wave voltage peak and the maximum echo voltage peak.

2. The ultrasonic flowmeter echo signal discrimination and processing system according to claim 1, characterized in that, A secondary trigger suppression circuit is provided between the output terminal of the second timer and the input terminal of the first timer.

3. The ultrasonic flowmeter echo signal discrimination and processing system according to claim 2, characterized in that, The peak detection module also includes a constant current switching circuit, the input terminal of which is connected to the given terminal of the echo signal, and the output terminal of which is connected to the input terminals of the two analog switching circuits.

4. The ultrasonic flowmeter echo signal discrimination and processing system according to claim 3, characterized in that, Each of the peak voltage storage units is connected in parallel with a release unit at both ends, and the control terminal of the release unit is connected to the data output terminal of the MCU microprocessor.

5. The ultrasonic flowmeter echo signal discrimination and processing system according to claim 4, characterized in that, A buffer circuit is provided between the peak detection module and the MCU microprocessor to ensure the stability of the signal output.

6. A method for processing echo signals from an ultrasonic flowmeter, characterized in that the method... include: S01, the threshold judgment module and the zero-point judgment module receive the echo signal; the threshold judgment module compares the amplitude of the first wave of the echo signal with the size of a set threshold and generates a comparison result signal; the zero-point judgment module automatically determines the zero-point position and generates a zero-point count signal whenever a zero point is detected; the threshold judgment module includes a voltage reference circuit for outputting a threshold voltage and a threshold comparator connected to the voltage reference circuit; the negative input terminal of the threshold comparator is connected to the output terminal of the voltage reference circuit, and the positive input terminal of the threshold comparator is connected to the echo signal setpoint terminal; S02, the threshold judgment module sends the comparison result signal to the timing module; the timing module includes a first timer and a second timer connected in parallel, and the clock input terminals of the first timer and the second timer are connected to the output terminal of the threshold comparator; the zero-point judgment module sends the zero-point count signal to the timing module; the timing module generates a time pulse signal of a specific duration; S03. The timing module sends the time pulse signal to the peak detection module. The peak detection module collects the voltage value information of the first wave voltage peak and the maximum echo voltage peak, and sends the voltage value information to the MCU microprocessor. The peak detection module includes two analog switch circuits and two peak voltage storage units. The control terminals of the two analog switch circuits are respectively connected to the output terminals of the first timer and the second timer. The input terminals of the two peak voltage storage units are respectively connected to the output terminals of the two analog switch circuits. The output terminals of the two peak voltage storage units are both connected to the data input terminal of the MCU microprocessor. The timing module sends the time pulse signal to the frequency output module. The zero-point judgment module sends the zero-point count signal to the frequency output module. The frequency output module generates frequency pulse information and sends the frequency pulse information to the MCU microprocessor. S04. The MCU microprocessor calculates the peak ratio based on the received voltage value information and obtains the ratio value; the MCU microprocessor obtains the discrimination result through the ratio value and the frequency pulse information.

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