Measuring device, measuring method and equipment for sound wave flying time

Abstract

The invention discloses a sound wave flying time measuring device, method and equipment, and belongs to the field of sound wave flying time measurement. The sound wave flying time measuring device comprises a control module, a pulse generating unit, a transducer assembly, a span time measuring module, a reference voltage generating unit and a comparator, the span time measurement module and the pulse generation unit are electrically connected with the control module; the pulse generating unit is electrically connected with the transducer assembly and the span time measuring module, the transducer assembly is electrically connected with the comparator, the comparator is electrically connected with the span time measuring module, and the transducer assembly is used for generating and transmitting a sound wave group and / or receiving the sound wave group; the pulse generation unit is used for generating and outputting a periodic initial pulse train, the initial pulse train can be transmitted to the span time measurement module and can be transmitted to the transducer assembly to serve as an excitation voltage pulse train, and the reference voltage generation unit is electrically connected with the control module and the comparator.

Description

Technical Field

[0001] The present application belongs to the field of acoustic wave transit time measurement, and specifically relates to an acoustic wave transit time measurement device, measurement method and equipment. Background Art

[0002] With the development of science and technology, the application of measurement by sound waves (including infrasound, sound waves with audible frequencies to human ears, and ultrasound) is becoming more and more widespread. Take the measurement of ultrasonic flight time as an example. Specifically, the ultrasonic wave is transmitted in the measuring tube, and the transmission time is affected by the fluid type and flow rate of the fluid in the measuring tube. Therefore, the parameter values ​​of the flow rate, flow rate, and other parameters of the fluid in the measuring tube can be determined by measuring the time of ultrasonic wave propagation and flight in the measuring tube, combined with the propagation speed of ultrasonic wave in the fluid. Among them, one or more groups of transducers are set at both ends of the measuring tube. When one end is used as an excitation transducer, the other end is used as a response transducer. After the excitation transducer is excited, an ultrasonic wave is generated. The ultrasonic wave propagates in the fluid in the measuring tube, and then the ultrasonic wave propagates to the response transducer. The time for the ultrasonic wave to propagate in the fluid in the measuring tube is regarded as the time interval from the excitation transducer generating the ultrasonic wave to the response transducer receiving the ultrasonic wave. The time for the ultrasonic wave to propagate in the fluid in the measuring tube is also called the flight time of the ultrasonic wave. By setting the position and direction of the transducer assembly, the acoustic wave flight time measurement technology can be used for ultrasonic ranging. However, in the related art, the method for measuring the flight time of ultrasonic flight cannot accurately determine the measurement results, especially in the case of noise interference, the measurement results will be wrong, resulting in inaccurate other parameter values ​​determined based on the flight time of ultrasonic flight, or even completely wrong parameter values. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a device, method and equipment for measuring the acoustic wave transit time, which solves the problem that the acoustic wave transit time measurement method in the related art cannot accurately determine the measurement result, and especially solves how to avoid accurately determining the acoustic wave transit time under the condition of noise interference, so as to avoid errors in the measured acoustic wave transit time result, thereby fundamentally avoiding the problem of inaccurate or erroneous values ​​of other parameters determined according to the acoustic wave transit time.

[0004] In a first aspect, an embodiment of the present application provides a device for measuring acoustic wave transit time, the device comprising: a control module, a pulse generating unit, a transducer assembly, a span time measuring module, a reference voltage generating unit and a comparator;

[0005] The span time measurement module and the pulse generating unit are both electrically connected to the control module; the pulse generating unit is electrically connected to the transducer assembly and the span time measurement module respectively, the transducer assembly is electrically connected to the comparator, the comparator is electrically connected to the span time measurement module, and the transducer assembly is used to generate and transmit a sound wave group, and / or receive a sound wave group;

[0006] The pulse generating unit is used to generate and output a periodic initial pulse group, the transducer assembly is used to generate and transmit an acoustic wave group, and the transducer assembly is also used to generate a response voltage wave group when receiving the acoustic wave group, and the response voltage wave group can be transmitted to the comparator;

[0007] The reference voltage generating unit is electrically connected to the control module and the comparator, and the reference voltage generating unit can generate a zero voltage or a non-zero voltage and output it to the comparator, so that the comparator performs a zero-crossing comparison and outputs a zero-crossing comparison pulse signal, or the comparator performs a non-zero comparison and outputs a non-zero comparison pulse signal;

[0008] The comparator transmits the comparison pulse signal to the span time measurement module, and the comparison pulse signal includes a zero-crossing comparison pulse signal or a non-zero comparison pulse signal. The span time measurement module is used to measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time, and / or to measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator for the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the sound wave flight time of the sound wave group. The selected response voltage wave group is: when the comparator works in the non-zero comparison mode, among the multiple non-zero comparison pulse signals output by the comparator for the response voltage wave group, the response voltage waves corresponding to all non-zero comparison pulse signals before the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal begins to decrease are the selected response voltage waves, and the wave group composed of all the selected response voltage waves is the selected response voltage wave group.

[0009] Optionally, the span time measurement module includes a first span time measurement unit, the first span time measurement unit is electrically connected to the comparator and the pulse generating unit respectively, the first span time measurement unit has a first mode and a second mode, and the first span time measurement unit can be switched between the first mode and the second mode;

[0010] When the first span time measurement unit is in the first mode, the first span time measurement unit is used to measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time; when the first span time measurement unit is in the second mode, the first span time measurement unit is used to measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator for the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the sound wave flight time of the sound wave group.

[0011] Optionally, the comparison pulse signal output by the comparator corresponding to the selected response voltage wave is recorded as the selected comparison pulse signal. When the first span time measurement unit is in the second mode, during the flight time measurement process of the acoustic wave group flight, the comparator first operates in the non-zero comparison mode, first performs a non-zero comparison on the response voltage wave group to output one or more non-zero comparison pulse signals, and then the comparator switches to the zero-crossing comparison mode, and then performs a zero-crossing comparison on the response voltage wave group to output multiple zero-crossing comparison pulse signals. The first span time measurement unit is used to: perform time counting sampling on the span time of the target edge of one or more zero-crossing comparison pulse signals after the last non-zero comparison pulse signal among the multiple selected comparison pulse signals corresponding to the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group, so as to obtain and cache one or more span time count values, so as to determine the span time, and then determine the acoustic wave flight time of the acoustic wave group;

[0012] Or, the first span time measurement unit is used to: perform time counting sampling on the span time of the target edge of each zero-crossing comparison pulse signal after the last non-zero comparison pulse signal among the multiple selected comparison pulse signals corresponding to the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group, until the measurement end mark arrives, or the number of the comparison pulse signals reaches a preset number threshold, so as to determine the span time, and then determine the sound wave flight time of the sound wave group; and cache the count value of each sampled span time, wherein, after the counting storage unit in the first span time measurement unit is full of data, when the count value of the new span time enters the counting storage unit, the span time count value that previously entered the counting storage unit overflows, so that the span time count value that later enters the counting storage unit can be cached.

[0013] Optionally, the span time measurement module includes a second span time measurement unit and a third span time measurement unit, the second span time measurement unit and the third span time measurement unit are both electrically connected to the comparator, and the pulse generating unit is electrically connected to the third span time measurement unit;

[0014] The second span time measurement unit is used to measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time; the third span time measurement unit is used to measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator of the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the sound wave flight time of the sound wave group.

[0015] Optionally, the response voltage wave group transmitted to the comparator can be transmitted to the span time measurement module, and the control module controls the reference voltage generating unit to provide the comparator with a comparison reference voltage greater than the zero-point voltage value, so that the comparator performs a non-zero comparison on the response voltage wave group. When a response voltage wave higher than the comparison reference voltage is compared by the comparator, the comparator outputs a non-zero comparison pulse signal. After one or more non-zero comparison pulse signals are output, the control module controls the reference voltage generating unit to provide the comparator with a comparison reference voltage equal to the zero-point voltage value, so that the comparator performs a zero-crossing comparison on the response voltage wave group and outputs one or more zero-crossing comparison pulse signals until the measurement process ends.

[0016] Optionally, the device for measuring the acoustic wave transit time further comprises a pulse counting unit;

[0017] The pulse counting unit is electrically connected to the control module and the comparator respectively, and is used to count the number of comparison pulse signals transmitted to the pulse counting unit, and transmit the counted number of comparison pulse signals to the control module.

[0018] Optionally, the span time measurement module is used to count the number of comparison pulse signals transmitted to the span time measurement module, and transmit the counted number of comparison pulse signals to the control module.

[0019] Optionally, the device for measuring the acoustic wave flight time further comprises an analog gate;

[0020] The analog gate is electrically connected to the pulse generating unit and the transducer assembly, and the analog gate is electrically connected to the comparator. The analog gate is switched on so that the excitation voltage wave group corresponding to the initial pulse group emitted by the pulse generating unit is transmitted to the comparator, or the response voltage wave group generated by the transducer assembly is transmitted to the comparator.

[0021] Optionally, the device for measuring the acoustic wave transit time further comprises a first output buffer and a second output buffer, and the transducer assembly comprises a first transducer and a second transducer;

[0022] The first output buffer is electrically connected to the pulse generating unit and the first transducer respectively, and the second output buffer is electrically connected to the pulse generating unit and the second transducer respectively;

[0023] One of the first transducer and the second transducer serves as an excitation transducer, and the other serves as a response transducer. When the first output buffer is configured as an output state and the second output buffer is configured as a cut-off state, the first output buffer provides an excitation voltage and a current to the first transducer, so that the first transducer serves as an excitation transducer and the second transducer serves as a response transducer. The first transducer generates and transmits a sound wave group, the second transducer receives the sound wave group and generates a response voltage wave group, and the response transducer is electrically connected to the comparator. When the second output buffer is configured as an output state and the first output buffer is configured as a cut-off state, the second output buffer provides an excitation voltage and a current to the second transducer, so that the second transducer serves as an excitation transducer and the first transducer serves as a response transducer. The second transducer generates and transmits a sound wave group, the first transducer receives the sound wave group and generates a response voltage wave group, and the response transducer is electrically connected to the comparator.

[0024] In a second aspect, an embodiment of the present application provides a method for measuring a sound wave span time, which is applied to the device for measuring the sound wave flight time described in any one of the first aspects above, and the measurement method includes:

[0025] Determine the number of selected comparison pulses;

[0026] Based on the number of selected comparison pulses, a reference span time of the acoustic wave flight time of the acoustic wave group is measured, and then the initial acoustic wave flight time is determined, wherein the reference span time is the span time of the target edge of the selected selected pulse signal relative to the target edge of the selected initial pulse signal;

[0027] Determine the number of selection and comparison pulses again. If the number of selection and comparison pulses measured twice is the same, the initial acoustic wave flight time is used as the effective acoustic wave flight time. If the number of selection and comparison pulses measured twice is different, redetermine the number of selection and comparison pulses, and remeasure and determine the initial acoustic wave flight time until the number of selection and comparison pulses measured twice is the same.

[0028] Optionally, the method for measuring the sound wave span time further includes:

[0029] Detect whether the initial acoustic wave flight time is valid.

[0030] Optionally, the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by zero comparison of at least two consecutive voltage waves in the selected response voltage wave group corresponding to the acoustic wave flying relative to the target edge of the same target pulse signal in the initial pulse group is measured, and the corresponding span time is determined, that is, the corresponding adjacent span time of at least two adjacent zero-crossing comparison pulse signals is obtained;

[0031] The detecting whether the initial acoustic wave flight time is valid comprises:

[0032] Subtract two adjacent span times to obtain the time difference between the adjacent span times; compare the obtained time difference with the pulse period of the pulse emitted by the pulse generating unit. If the time difference between the adjacent span times and the difference between the pulse period are within a preset difference range, then both of the two adjacent span times are valid, and the corresponding initial sound wave flight time is valid; if the time difference between the adjacent span times and the difference between the pulse period are outside the preset difference range, then both of the two adjacent span times are invalid, and the corresponding initial sound wave flight time is invalid.

[0033] Optionally, the comparator operates in a non-zero comparison mode; and the determining the number of selected comparison pulses comprises:

[0034] The comparator operates in a non-zero comparison mode, and measures the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal output by the comparator after the non-zero comparison of the response voltage wave group, so as to determine the span time from the leading edge to the trailing edge of the comparison pulse signal in combination with the counting resolution;

[0035] The wave group consisting of the response voltage waves corresponding to all non-zero comparison output pulses before the span time starts to decrease is the selected response voltage wave group, and the comparison pulses corresponding to the selected response voltage wave group are all selected comparison pulses to determine the number of selected comparison pulses.

[0036] Optionally, the measuring of the reference span time of the acoustic wave transit time of the acoustic wave group based on the selected comparison pulse quantity, and then determining the initial acoustic wave transit time, comprises:

[0037] Initial acoustic wave flight time = reference span time - pulse period x(N-C) of initial pulse group + pulse period x(LD) of initial pulse group;

[0038] Among them, N represents the number of pulses in the initial pulse group, L represents the number of the selected comparison pulses, D represents that the Dth selected comparison pulse is selected, and C represents that the Cth initial pulse signal is selected in the initial pulse signal.

[0039] In a third aspect, an embodiment of the present application provides a device, which includes a device for measuring the acoustic wave transit time as described in any one of the first aspects above.

[0040] In the embodiment of the present application, since the span time measurement module and the pulse generating unit are both electrically connected to the control module, the span time measurement module and the pulse generating unit can be controlled by the control module, or the span time measurement module sends a signal to the control module, or the control module can collect the required data from the span time measurement module. Since the pulse generating unit is electrically connected to the transducer assembly and the span time measurement module respectively, and the transducer assembly is electrically connected to the comparator, once the pulse generating unit generates an initial pulse group, the initial pulse group can be transmitted to the transducer assembly and the span time measurement module. After the initial pulse group is transmitted to the span time measurement module, the span time measurement module can use a certain edge of a certain pulse signal received from the initial pulse group as the counting starting point for determining the span time used for the acoustic wave flight time. In order to simplify the design and the expression, the leading edge of the first pulse signal received from the initial pulse group is usually selected as the counting starting point for determining the span time used for the acoustic wave flight time. After receiving the initial pulse group, the transducer assembly uses the initial pulse group or its enhanced signal group as an excitation voltage pulse group to excite the transducer assembly to generate and emit a sound wave group, and the transducer assembly generates a response voltage wave group when receiving the sound wave group. Since the transducer assembly is electrically connected to the comparator, the response voltage wave group can be transmitted to the comparator, and the comparator can receive the response voltage wave group to compare and output a comparison pulse signal. The comparator is electrically connected to the span time measurement module, so that the comparison pulse signal can be transmitted to the span time measurement module, and the span time measurement module can measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time, and / or measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator after the selected response voltage wave group is compared with the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the sound wave flight time of the sound wave group. That is, in the embodiment of the present application, by setting a comparator and a span time measurement module, the span time measurement module can receive the comparison pulse signal output by the comparator, thereby accurately determining the span time from the leading edge to the trailing edge of the comparison pulse signal, and / or the flight time of the sound wave in the sound wave group, that is, accurately determining the flight time of the sound wave group, and then more accurately determining the corresponding other parameter values ​​according to the flight time of the sound wave group. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 One of the schematic diagrams showing a device for measuring the acoustic wave transit time provided in an embodiment of the present application;

[0042] Figure 2 A second schematic diagram showing a device for measuring a sound wave transit time provided in an embodiment of the present application;

[0043] Figure 3One of the schematic diagrams showing a fluid flow measurement device based on an acoustic wave span time measurement device and technology provided in an embodiment of the present application;

[0044] Figure 4 A second schematic diagram showing a fluid flow measurement device based on an acoustic wave span time measurement device and technology provided in an embodiment of the present application;

[0045] Figure 5 One of the schematic diagrams showing an ultrasonic distance measuring device based on a sound wave span time measuring device and technology provided in an embodiment of the present application;

[0046] Figure 6 A second schematic diagram showing an ultrasonic distance measuring device based on a sound wave span time measuring device and technology provided in an embodiment of the present application;

[0047] Figure 7 A schematic diagram showing the measurement principle of a device for measuring acoustic wave transit time provided in an embodiment of the present application;

[0048] Figure 8 A flow chart showing a method for measuring a sound wave span time provided in an embodiment of the present application.

[0049] Reference numerals:

[0050] 10: control module; 101: controller; 102: integrated control unit; 20: pulse generating unit; 30: transducer assembly; 31: first transducer; 32: second transducer; 33: third transducer; 40: span time measurement module; 41: first span time measurement unit; 42: second span time measurement unit; 43: third span time measurement unit; 50: comparator; 60: reference voltage generating unit; 70: pulse counting unit; 80: analog gate; 90: first output buffer; 100: second output buffer; 110: measuring tube. DETAILED DESCRIPTION

[0051] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0052] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0053] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0054] like Figures 1 to 7 As shown, the device for measuring the acoustic wave transit time includes: a control module 10 , a pulse generating unit 20 , a transducer assembly 30 , a span time measuring module 40 , a reference voltage generating unit 60 and a comparator 50 .

[0055] The span time measurement module 40 and the pulse generating unit 20 are both electrically connected to the control module 10; the pulse generating unit 20 is electrically connected to the transducer assembly 30 and the span time measurement module 40 respectively, the transducer assembly 30 is electrically connected to the comparator 50, the comparator 50 is electrically connected to the span time measurement module 40, the transducer assembly 30 is used to generate and transmit sound wave groups, and / or, receive sound wave groups; the pulse generating unit 20 is used to generate and output periodic initial pulse groups, the initial pulse groups can be transmitted to the span time measurement module 40, and the initial pulse The group can be transmitted to the transducer assembly 30 for use as an excitation voltage pulse group; the transducer assembly 30 is used to stimulate the transducer assembly 30 to generate and emit an acoustic wave group when receiving the excitation voltage pulse group, and the transducer assembly 30 is also used to generate a response voltage wave group when receiving the acoustic wave group, and the response voltage wave group can be transmitted to the comparator 50; the reference voltage generating unit 60 is electrically connected to the control module 10 and the comparator 50, and the reference voltage generating unit 60 can generate a zero-point voltage or a non-zero voltage and output it to the comparator 50, so that the comparator 50 performs a zero-crossing comparison and outputs a crossing voltage. The comparator 50 performs a non-zero comparison and outputs a non-zero comparison pulse signal; the comparator 50 transmits the comparison pulse signal to the span time measurement module 40, the comparison pulse signal includes a zero-crossing comparison pulse signal or a non-zero comparison pulse signal, and the span time measurement module 40 is used to measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time, and / or to measure the target edge of the zero-crossing comparison pulse signal output by the comparator 50 after the selected response voltage wave group is compared with the selected voltage wave group in the initial pulse group. The count value of the span time of the target edge of the fixed pulse signal is used to determine the span time, and then the sound wave flying time of the sound wave group is determined. The selected response voltage wave group is: when the comparator 50 works in the non-zero comparison mode, among the multiple non-zero comparison pulse signals output by the response voltage wave group after non-zero comparison by the comparator 50, the response voltage waves corresponding to all non-zero comparison pulse signals before the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal begins to decrease are the selected response voltage waves, and the wave group composed of all the selected response voltage waves is the selected response voltage wave group.

[0056] In the embodiment of the present application, since the span time measurement module 40 and the pulse generation unit 20 are both electrically connected to the control module 10, the span time measurement module 40 and the pulse generation unit 20 can be controlled by the control module 10, or the span time measurement module 40 sends a signal to the control module 10, or the control module 10 can collect the required data from the span time measurement module 40. Since the pulse generation unit 20 is electrically connected to the transducer assembly 30 and the span time measurement module 40, respectively, and the transducer assembly 30 is electrically connected to the comparator 50, once the pulse generation unit 20 generates an initial pulse group, the initial pulse group can be transmitted to the transducer assembly 30 and the span time measurement module 40. After the initial pulse group is transmitted to the span time measurement module 40, the span time measurement module 40 can use a certain edge of a certain pulse signal received from the initial pulse group as the counting starting point of the span time used to determine the acoustic wave flight time. In order to simplify the design and the expression, the leading edge of the first pulse signal received from the initial pulse group is usually selected as the counting starting point of the span time used to determine the acoustic wave flight time. After receiving the initial pulse group, the transducer assembly 30 uses the initial pulse group or its enhanced signal group as an excitation voltage pulse group to excite the transducer assembly 30 to generate and emit a sound wave group, and the transducer assembly 30 generates a response voltage wave group when receiving the sound wave group. Since the transducer assembly 30 is electrically connected to the comparator 50, the response voltage wave group can be transmitted to the comparator 50, and the comparator 50 can receive the response voltage wave group to compare and output a comparison pulse signal. The comparator 50 is electrically connected to the span time measurement module 40, so that the comparison pulse signal can be transmitted to the span time measurement module 40, and the span time measurement module 40 can measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time, and / or measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator 50 after the selected response voltage wave group is compared with the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the sound wave flight time of the sound wave group. That is, in the embodiment of the present application, by setting the comparator 50 and the span time measurement module 40, the span time measurement module 40 can receive the comparison pulse signal output by the comparator 50, so as to accurately determine the span time from the leading edge to the trailing edge of the comparison pulse signal, and / or the sound wave transit time of the sound wave group, and then can accurately determine the corresponding other parameter values ​​according to the sound wave transit time of the sound wave group.

[0057] It should be noted that the initial pulse group generated by the pulse generating unit 20 is usually a periodic square wave or rectangular wave pulse. Of course, the initial pulse group generated by the pulse generating unit 20 can also be a periodic triangle wave or other periodic waves. The specific type of the initial pulse group generated by the pulse generating unit 20 is not limited in the embodiment of the present application. For the sake of convenience, the embodiment of the present application takes the initial pulse group generated by the pulse generating unit 20 as a periodic square wave to illustrate the principle of the invention. Correspondingly, the sound wave group and the response voltage wave are quasi-sine waves.

[0058] It should also be noted that the initial pulse signal has a leading edge and a trailing edge, and the target edge of the initial pulse signal can be a leading edge or a trailing edge, and the embodiments of the present application do not limit this; the zero-crossing comparison pulse signal has a leading edge and a trailing edge, and the target edge of the zero-crossing comparison pulse signal can be a leading edge or a trailing edge, and the embodiments of the present application do not limit this; the selected pulse signal has a leading edge and a trailing edge, and the target edge of the selected pulse signal can be a leading edge or a trailing edge, and the embodiments of the present application do not limit this.

[0059] In addition, in some embodiments, Figure 1 As shown, the device for measuring the acoustic wave flight time may further include a first output buffer 90 and a second output buffer 100, and the transducer assembly 30 includes a first transducer 31 and a second transducer 32; the first output buffer 90 is electrically connected to the pulse generating unit 20 and the first transducer 31 respectively, and the second output buffer 100 is electrically connected to the pulse generating unit 20 and the second transducer 32 respectively; when one of the first transducer 31 and the second transducer 32 is used as an excitation transducer, the other is used as a response transducer, when the first output buffer 90 is configured as an output state and the second output buffer 100 is configured as a cut-off state, the first output buffer 90 provides an excitation voltage and a current for the first transducer 31, So that the first transducer 31 acts as an excitation transducer, the second transducer 32 acts as a response transducer, the first transducer 31 generates and transmits a sound wave group, the second transducer 32 receives the sound wave group and generates a response voltage wave group, and the response transducer is electrically connected to the comparator 50; when the second output buffer 100 is configured to the output state and the first output buffer 90 is configured to the cut-off state, the second output buffer 100 provides an excitation voltage and current to the second transducer 32, so that the second transducer 32 acts as an excitation transducer, the first transducer 31 acts as a response transducer, the second transducer 32 generates and transmits a sound wave group, the first transducer 31 receives the sound wave group and generates a response voltage wave group, and the response transducer is electrically connected to the comparator 50.

[0060] Since the first output buffer 90 is electrically connected to the pulse generating unit 20 and the first transducer 31 respectively, and the second output buffer 100 is electrically connected to the pulse generating unit 20 and the second transducer 32 respectively, the function of the first transducer 31 and the function of the second transducer 32 can be switched by configuring the states of the first output buffer 90 and the second output buffer 100. Specifically, when the first output buffer 90 is configured to be in the output state and the second output buffer 100 is configured to be in the cut-off state, the first output buffer 90 can provide the first transducer 31 with an excitation voltage and current, and the second output buffer 100 does not provide the second transducer 32 with an excitation voltage and current, so that the first transducer 31 is excited, the first transducer 31 acts as an excitation transducer, and the second transducer 32 acts as a response transducer, and the first transducer 31 generates and transmits a sound wave group. After the sound wave group is transmitted, the second transducer 32 can receive the sound wave group and generate a response voltage wave group, and the response transducer is electrically connected to the comparator 50, so that the response voltage group can be transmitted to the comparator 50. 0; when the second output buffer 100 is configured as the output state and the first output buffer 90 is configured as the cut-off state, the second output buffer 100 can provide the second transducer 32 with an excitation voltage and current, and the first output buffer 90 does not provide the first transducer 31 with an excitation voltage and current, so that the second transducer 32 is excited, the second transducer 32 acts as an excitation transducer, and the first transducer 31 acts as a response transducer, the second transducer 32 generates and transmits a sound wave group, and after the sound wave group is transmitted, the first transducer 31 can receive the sound wave group and generate a response voltage wave group, and the response transducer is electrically connected to the comparator 50, so that the response voltage wave group can be transmitted to the comparator 50.

[0061] It should be noted that in the embodiments of the present application, Figure 5 As shown, the distance can be measured by using the measuring device of the acoustic wave flight time. At this time, the first output buffer 90 can provide the excitation voltage and current to the first transducer 31, and the second output buffer 100 is in the cut-off state. The first transducer 31 acts as an excitation transducer, and the second transducer 32 acts as a response transducer. After the excitation transducer emits the sound wave, the sound wave is transmitted to the obstacle, and the sound wave is blocked by the obstacle and reflected to the second transducer 32, so that the sound wave is transmitted to the response transducer, and the response transducer can generate a response voltage wave, and then the acoustic wave flight time can be accurately determined. By using the speed of the acoustic wave transmission in the current medium, the distance between the excitation transducer and the obstacle can be accurately determined. For example, the measuring device of the acoustic wave flight time in the embodiment of the present application is installed on a vehicle, a ship, or a submarine, so that the distance between the measuring device of the acoustic wave flight time and the obstacle can be more accurately determined.

[0062] Or, in the embodiment of the present application, Figure 6 As shown, the measuring device for the acoustic wave flight time may further include a first output buffer 90, and the transducer assembly 30 may include a third transducer 33. The first output buffer 90 is electrically connected to the pulse generating unit 20 and the third transducer 33 respectively. At this time, the first output buffer 90 may be controlled to be in an output state first, so that the first output buffer 90 provides an excitation voltage and current to the third transducer 33, and the first transducer 31 acts as an excitation transducer. After the excitation transducer emits an acoustic wave, the first output buffer 90 is controlled to switch to a cut-off state, and the third transducer 33 is converted into a response transducer. The acoustic wave is transmitted to an obstacle, and the acoustic wave is blocked by the obstacle and reflected back to the third transducer 33, so that the acoustic wave is transmitted to the response transducer, and the response transducer can generate a response voltage wave, thereby accurately determining the acoustic wave flight time, and utilizing the speed of acoustic wave transmission in the current medium, thereby accurately determining the distance between the excitation transducer and the obstacle. For example, the device for measuring the acoustic wave transit time in the embodiment of the present application is installed on a vehicle, a ship, or a submarine, so that the distance between the device for measuring the acoustic wave transit time and an obstacle can be determined more accurately.

[0063] In addition, in the embodiment of the present application, the span time measurement module 40 is equivalent to having two modes, that is, the span time measurement module 40 has a first mode and a second mode. When the span time measurement module 40 is in the first mode, the span time measurement module 40 measures the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time; when the span time measurement module 40 is in the second mode, the span time measurement module 40 measures the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator for the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the sound wave flight time of the sound wave group.

[0064] Among them, when the span time measurement module 40 is in the first mode, the span time measurement module 40 measures the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal. When it is necessary to determine the span time from the leading edge to the trailing edge of the comparison pulse signal, the count value of the span time from the leading edge to the trailing edge is multiplied by the count resolution of the span time measurement module 40 to determine the span time from the leading edge to the trailing edge of the comparison pulse signal. Since the response voltage wave will inevitably decay after the initial pulse group is transmitted, the non-zero comparison pulse signal output by the comparator 50 will inevitably decay after the response voltage wave is transmitted to the comparator 50. Under the premise that the non-zero comparison reference voltage of the comparator remains unchanged, when the receiving transducer reaches the resonant state, the width of the non-zero comparison pulse signal remains stable, and the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal is a fixed value. Once the initial pulse group is finished transmitting, the comparison pulse signal will inevitably decay. At this time, the pulse width of the non-zero comparison pulse signal will decrease, that is, the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal will decrease. Therefore, by determining the span time from the leading edge to the trailing edge of the comparison pulse signal, it is possible to accurately determine when the comparison pulse signal begins to decay, and the sign signal of the comparison pulse signal starting to decrease can be used as the termination sign of the acoustic wave flyby measurement. In addition, the previous adjacent comparison pulse of the comparison pulse at which the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal begins to decrease is the comparison pulse corresponding to the response wave when the acoustic wave excited by the last initial pulse in the initial pulse group reaches the receiving transducer, and is the response pulse corresponding to the last initial pulse, which is called the "last response pulse". Because the pulses in the initial pulse group are periodic pulses, any edge of any pulse in the initial pulse group transmitted to the span time measurement module 40 can be used as the counting starting point for determining the span time used for determining the acoustic wave flight time, that is, the counting starting point of the span time is determined, so that the counting value of the span time obtained by the span time measurement module is accurate, and then the acoustic wave flight time can be accurately determined. For the sake of simplifying the device design and concise principle description, the present application selects the leading edge of the first pulse in the initial pulse group transmitted to the span time measurement module 40 as the counting starting point for determining the span time used for determining the acoustic wave flight time.

[0065] In addition, if Figure 4As shown, the initial pulse group is transmitted to the transducer assembly 30, and the transducer assembly 30 generates and emits a sound wave group. The sound wave group is transmitted to the transducer assembly 30, so that the transducer assembly 30 generates a response voltage wave group, which is equivalent to the initial pulse group continuously exciting the transducer assembly 30. When the transducer assembly 30 is initially excited, the generated response voltage wave group is transmitted to the comparator 50. Then, the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal output by the comparator 50 must gradually increase until the transducer assembly 30 reaches a resonance with the same period and frequency as the initial pulse group. At this time, the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal reaches a maximum value and remains stable. Once the pulse generating unit 20 stops generating the initial pulse group, it is equivalent to stopping the energy injection into the transmitting transducer of the transducer assembly 30. The transducer assembly 30 will inevitably stop generating and transmitting the sound wave group, and the corresponding sound wave group will stop being transmitted to the receiving transducer of the transducer assembly 30. Therefore, the response voltage wave in the response voltage wave group generated by the receiving transducer of the transducer assembly 30 will inevitably begin to decay, so that the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal output by the non-zero comparison will inevitably decrease. In this process, the comparison reference voltage of the non-zero comparison of the comparator remains unchanged. In order to simplify the device design and the principle description, the comparison reference voltage of the non-zero comparison is usually set to a positive voltage greater than the zero voltage of the comparator, such as a voltage of 50% of the peak voltage value.

[0066] In addition, in the embodiment of the present application, the comparison pulse signal output by the comparator corresponding to the selected response voltage wave is recorded as the selected comparison pulse signal. The selected comparison pulse signal may include a zero-crossing comparison pulse signal and a non-zero comparison pulse signal.

[0067] In addition, in the embodiment of the present application, when the span time measurement module 40 is in the first mode, the control module controls the reference voltage generation unit 80 to generate a non-zero voltage and output it to the comparator, and the comparator performs a non-zero comparison, that is, the comparator outputs a non-zero comparison pulse signal, so that the span time measurement module 40 measures the count value of the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal to determine the span time. For example, Figure 7 As shown, when the span time measurement module 40 is in the first mode, the comparator performs a non-zero comparison, and the comparison pulse signal of the non-zero comparison pulse is as follows: Figure 7 The pulses in .

[0068] In addition, when the span time measurement module 40 is in the second mode, the span time measurement module 40 measures the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator for the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the acoustic wave flying time of the acoustic wave group. When it is necessary to determine the span time of the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator for the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group, the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator for the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group can be directly multiplied by the counting resolution of the span time measurement module 40 to obtain the span time, and then the flying time of the initial pulse group can be conveniently determined.

[0069] Among them, when the span time measurement module 40 is in the second mode, the control module 10 controls the reference voltage generation unit 60 to output a non-zero voltage to the comparator 50 first, so that the comparator 50 performs a non-zero comparison and outputs a non-zero comparison pulse signal. After the comparator 50 outputs one or more non-zero comparison pulse signals, the control module 10 controls the reference voltage generation unit 60 to output a zero-point voltage to the comparator 50, so that the comparator 50 performs a zero-crossing comparison and outputs a zero-crossing comparison pulse signal, so that the comparison pulse signal corresponding to the selected response voltage wave will include a non-zero comparison pulse signal and a zero-crossing comparison pulse signal. For example, Figure 7 As shown, the comparison pulse signal of the comparison reference switching is the comparison pulse signal corresponding to the selected response voltage wave, and the comparison pulse signal includes a non-zero comparison pulse signal and a zero-crossing comparison pulse signal, such as Figure 7 As shown, there are L comparison pulse signals corresponding to the selected response voltage wave, including K zero-crossing comparison signals.

[0070] In addition, in an embodiment of the present application, after installing the measuring tube 110 in the device for measuring the acoustic wave flight time, the transducer assembly can be installed at both ends of the measuring tube 110, and the fluid flows through the measuring tube 110. The transducer assembly includes a first transducer 31 and a second transducer 32. One of the first transducer 31 and the second transducer 32 can be used as a transmitting transducer, and the other is used as a receiving transducer. After the transmitting transducer is excited, an ultrasonic wave is generated. The ultrasonic wave is transmitted in the measuring tube 110, and then the ultrasonic wave is transmitted to the receiving transducer. The excitation voltage wave group transmitted by the initial pulse group to the transmitting transducer stimulates the transmitting transducer to generate and transmit an ultrasonic wave group. The span time of a certain ultrasonic wave in the ultrasonic wave group from the transmitting transducer to the receiving transducer is the ultrasonic wave flight time. Since the pulse of the initial pulse group used in this application is a periodic pulse, the corresponding excited ultrasonic wave group also has a periodic characteristic. Therefore, the flight time of the last sound wave in the ultrasonic wave group is equal to the flight time of any sound wave in the wave group. In view of the limited transmission distance of the electrical signal and the acoustic signal in the device of the application, the transmission time of the electrical signal can be ignored compared with the transmission time and the flight time of the acoustic signal. Figure 7 As shown, the span time of the leading edge / trailing edge of the last selected pulse signal relative to the leading edge / trailing edge of the last initial pulse is equivalent to the acoustic wave flight time of the acoustic wave group, but there are technical difficulties in directly measuring the acoustic wave flight time, and it is even not feasible in some scenarios. The span time of the leading edge of the last selected pulse signal relative to the leading edge of the first initial pulse signal is used as the reference span time, or the span time of the trailing edge of the last selected pulse signal relative to the trailing edge of the first initial pulse signal is used as the reference span time. Since the pulses in the initial pulse group are periodic, the number of pulses can be pre-set, and the measurement and counting of the reference span time are convenient and feasible. Therefore, the measurement of the acoustic wave flight time of the acoustic wave group can be converted into the measurement of the reference span time, that is:

[0071] The acoustic wave transit time of the acoustic wave group = reference span time - pulse period x of the initial pulse group (number of pulses of the initial pulse group - 1).

[0072] For example, Figure 7 As shown, the span time of the pulse signal starts to decrease after the Kth zero-crossing comparison pulse in the comparison pulse signal of the comparison reference switching, that is, the Kth zero-crossing comparison pulse and all the zero-crossing comparison pulses and non-zero comparison pulses before it are selected comparison pulses, and the Kth zero-crossing comparison pulse signal is the response comparison pulse of the last pulse (the Nth pulse in the figure) in the initial pulse group, so it can be set as:

[0073] Reference span time = the span time of the leading edge of the Kth zero-crossing comparison pulse signal relative to the leading edge of the first initial pulse signal;

[0074] Or, reference span time = the span time of the trailing edge of the Kth zero-crossing comparison pulse signal relative to the trailing edge of the first initial pulse signal;

[0075] Of course, the reference span time can be selected as the span time of the leading edge / trailing edge of any zero-crossing comparison pulse signal relative to the leading edge / trailing edge of any initial pulse signal. This application does not make any limitation. For the sake of design simplicity and simplicity of expression, this application uses the reference span time selected as the span time of the leading edge of the Kth zero-crossing comparison pulse signal relative to the leading edge of the first initial pulse signal to illustrate the principle of this application.

[0076] It should be noted that the flight time of any sound wave in the initial sound wave group is equal to the flight time of any other sound wave in the initial sound wave group. Figure 7 As shown, the Nth sound wave in the initial sound wave group, that is, the flight time of the Nth sound wave is equal to the flight time of any other sound wave in the initial sound wave group. After the initial pulse group is transmitted to the transducer assembly, the transducer assembly excites to generate an excitation voltage wave group, so that the time of the initial pulse group and the time of the excitation voltage wave group can be considered equal.

[0077] In addition, in the embodiment of the present application, the transducer assembly 30 is an energy conversion device that can work bidirectionally, and can both emit sound waves and receive sound waves. That is, after the transducer assembly 30 driven by the pulse generating unit 20 receives the initial pulse group, the transducer assembly 30 can be excited to generate and emit a sound wave group, and the transducer assembly 30 not driven by the pulse generating unit 20 will generate a response voltage wave group when receiving the sound wave group. Of course, the transducer assembly 30 may include a first transducer 31 and a second transducer 32, the first transducer 31 receives the initial pulse group and is excited to generate a sound wave group, and the second transducer 32 receives the sound wave group to generate a response voltage wave group, and vice versa. Alternatively, the transducer assembly 30 may only include a third transducer 33, the third transducer 33 receives the initial pulse group and is excited to generate a sound wave group, and when the third transducer 33 does not receive the initial pulse group, the third transducer 33 receives the sound wave group to generate a response voltage wave group.

[0078] In addition, in the embodiment of the present application, if the initial pulse group is directly transmitted to the span time measurement module 40 as the first transmission path of the initial pulse group, and the initial pulse group is transmitted to the span time measurement module 40 after passing through the comparator 50 as the second transmission path of the initial pulse group, in the embodiment of the present application, the time when the initial pulse group is received by the span time measurement module 40 can be the time when it is transmitted to the span time measurement module 40 through the first transmission path, or can be the time when it is transmitted to the span time measurement module 40 through the second transmission path. That is, in the embodiment of the present application, the initial pulse group generated by the pulse generating unit 20 can be directly transmitted to the span time measurement module 40, and the span time measurement module 40 can use a certain edge of a certain pulse signal of the received initial pulse group as the counting starting point of the span time used to determine the acoustic wave flying time; the initial pulse group generated by the pulse generating unit 20 can also be transmitted to the span time measurement module 40 after passing through the comparator 50, and the span time measurement module 40 can use a certain edge of a certain pulse signal of the received initial pulse group as the counting starting point of the span time used to determine the acoustic wave flying time. Among them, the initial pulse group is an electrical signal, and the propagation speed of the electrical signal is the same as the speed of light, which is much greater than the propagation speed of the sound wave. In the embodiment of the present application, the propagation of the electrical signal is in the limited space of the device, so the propagation distance of the electrical signal is very short. Therefore, the propagation time of the electrical signal in the embodiment of the present application can be ignored. When the span time measurement module 40 receives the initial pulse group, whether it is the initial pulse group transmitted through the first transmission path or the initial pulse group transmitted through the second transmission path, the path delay of the two transmission paths can be ignored. For the measurement of the acoustic wave flight time, the two transmission paths can be considered to be equivalent. Therefore, in actual use, between the first transmission path and the second transmission path, the initial pulse group transmitted by any transmission path can be selected, and this application does not make specific restrictions. Specifically, if the first transmission path is used as the transmission path of the initial pulse group so that it transmits the initial pulse group to the span time measurement module 40, the initial pulse group can be not transmitted to the comparator 50, which is equivalent to disconnecting the pulse generating unit from the comparator 50; if the second transmission path is used as the transmission path of the initial pulse group so that it transmits the initial pulse group to the span time measurement module 40, the pulse generating unit from the span time measurement module 40 can be disconnected or the span time measurement module 40 is set to ignore the initial pulse group transmitted by the pulse generating unit 20. For the sake of simplicity, the present application chooses to use the first transmission path to illustrate the principle of the present invention.

[0079] In addition, in the embodiment of the present application, once the span time measurement module 40 measures the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal, when determining the span time from the leading edge to the trailing edge of the comparison pulse signal, the count value of the span time from the leading edge to the trailing edge can be directly multiplied by the count resolution of the span time measurement module to obtain the span time from the leading edge to the trailing edge.

[0080] In addition, in some embodiments, Figure 1 As shown, the span time measurement module 40 includes a first span time measurement unit 41, which is electrically connected to the comparator 50 and the pulse generating unit 20 respectively, and has a first mode and a second mode, and the first span time measurement unit 41 can be switched between the first mode and the second mode; when the first span time measurement unit 41 is in the first mode, the first span time measurement unit 41 is used to measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time; when the first span time measurement unit 41 is in the second mode, the first span time measurement unit 41 is used to measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator 50 for the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the acoustic wave flight time of the acoustic wave group. Through such a setting, it is equivalent to completing the measurement of the span time from the leading edge to the trailing edge of the comparison pulse signal and / or completing the measurement of the sound wave flight time of the sound wave group by only one span time measurement unit, thereby saving costs.

[0081] It should be noted that when the first span time measurement unit 41 is in the first mode, the comparator 50 performs a non-zero comparison and outputs a non-zero comparison pulse signal, and when the first span time measurement unit 41 is in the second mode, the comparator 50 first performs a non-zero comparison and outputs one or more non-zero comparison pulse signals, and then the comparator 50 performs a zero-crossing comparison and outputs multiple zero-crossing comparison pulse signals. That is, the comparator 50 can switch from a non-zero comparison to a zero-crossing comparison.

[0082] In addition, in some embodiments, the comparison pulse signal output by the comparator corresponding to the selected response voltage wave is recorded as the selected comparison pulse signal. When the first span time measurement unit 41 is in the second mode, the first span time measurement unit 41 is used to: perform time counting sampling on the span time of the target edge of one or more zero-crossing comparison pulse signals after the last non-zero comparison pulse signal in the multiple selected comparison pulse signals corresponding to the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group, so as to obtain and cache the count values ​​of one or more span times, so as to determine the corresponding span time, and then determine the acoustic wave flight time of the acoustic wave group; or, the first span time measurement unit 41 is used to: perform time counting sampling on the target edge of the one or more zero-crossing comparison pulse signals after the last non-zero comparison pulse signal in the multiple selected comparison pulse signals corresponding to the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group, so as to obtain and cache the count values ​​of one or more span times, so as to determine the corresponding span time, and then determine the acoustic wave flight time of the acoustic wave group; or, The target edge of each zero-crossing comparison pulse signal after the last non-zero comparison pulse signal in the corresponding multiple selected comparison pulse signals is time counted and sampled relative to the span time of the target edge of the selected pulse signal in the initial pulse group until the measurement end mark arrives, or the number of comparison pulse signals reaches a preset number threshold, so as to determine the corresponding span time, and then determine the sound wave flight time of the sound wave group; and cache the count value of each sampled span time, wherein, after the counting storage unit in the first span time measurement unit 41 is full of data, when the count value of the new span time enters the counting storage unit, the span time count value that previously entered the counting storage unit overflows, so that the span time count value that enters the counting storage unit later can be cached.

[0083] Among them, when the first span time measurement unit 41 is in the second mode, the first span time measurement unit 41 can only perform time counting sampling on the span time of the target edge of a zero-crossing comparison pulse signal after the last non-zero comparison pulse signal in the multiple selected comparison pulse signals corresponding to the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group. At this time, a span time count value is obtained, and the time count value is cached; the first span time measurement unit 41 can also perform time counting sampling on the span time of the target edge of multiple zero-crossing comparison pulse signals after the last non-zero comparison pulse signal in the multiple selected comparison pulse signals corresponding to the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group. Among them, when the first span time measurement unit 41 is in the second mode, the comparator 50 can only output a non-zero comparison pulse signal, and then the comparator 50 switches to perform zero-crossing comparison to output a zero-crossing comparison pulse signal. At this time, the last non-zero comparison pulse signal among the multiple selected comparison pulse signals corresponding to the selected response voltage wave group is also the first non-zero comparison pulse signal; after the comparator 50 outputs multiple non-zero comparison pulse signals, the comparator 50 switches to perform zero-crossing comparison to output a zero-crossing comparison pulse signal. At this time, among the multiple selected comparison pulse signals corresponding to the selected response voltage wave group, the last non-zero comparison pulse signal is the last non-zero comparison pulse signal among the multiple non-zero comparison pulse signals output by the comparator.

[0084] For example, the comparator 50 outputs a non-zero comparison pulse signal, the comparator 50 only outputs one non-zero comparison pulse signal, and then the first span time measurement unit 41 starts time counting sampling from the first zero-crossing comparison pulse signal after the last (also the first) non-zero comparison pulse, which is equivalent to the first span time measurement unit 41 offsetting 1 comparison pulse signal, that is, offsetting 0 zero-crossing comparison pulse signals for time counting sampling; for another example, the comparator 50 outputs 6 non-zero comparison pulse signals, and then the first span time measurement unit 41 starts time counting sampling from the third zero-crossing comparison pulse signal after the last non-zero comparison pulse, which is equivalent to the first express time measurement unit 41 offsetting 8 comparison pulse signals, that is, offsetting 2 zero-crossing comparison pulse signals before starting time counting sampling.

[0085] Of course, the first span time measurement unit 41 can also cache the sampled span time count value according to the first-in-first-out principle, that is, the first span time measurement unit 41 performs continuous sampling. Specifically, the first span time measurement unit 41 performs time counting sampling on the span time of the target edge of each zero-crossing comparison pulse signal after the last non-zero comparison pulse signal in the multiple selected comparison pulse signals corresponding to the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group until the measurement end mark arrives, or the number of comparison pulse signals reaches a preset number threshold, and caches the sampled count value of each span time. After the counting storage unit of the first span time measurement unit 41 is full of data, when the count value of the new span time enters the first span time measurement unit 41, the count value of the span time that first enters the counting storage unit of the first span time measurement unit 41 overflows, so that the count value of the span time that enters the counting storage unit of the first span time measurement unit 41 later can be cached.

[0086] It should be noted that the number of the counting storage units of the first span time measurement unit 41 can be set according to actual needs, for example, the number of the counting storage units is 3, and for another example, the number of the counting storage units is 4. This embodiment of the present application does not limit this.

[0087] In addition, in some embodiments, Figure 2 As shown, the span time measurement module 40 includes a second span time measurement unit 42 and a third span time measurement unit 43, the second span time measurement unit 42 and the third span time measurement unit 43 are both electrically connected to the comparator 50, and the third span time measurement unit 43 is electrically connected to the pulse generating unit 20; the second span time measurement unit 42 is used to measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time; the third span time measurement unit 43 is used to measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator for the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the sound wave flight time of the sound wave group.

[0088] Through such an arrangement, the second span time measurement unit 42 can measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time, and the third span time measurement unit 43 can measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator of the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the sound wave flight time of the sound wave group. The function of each span time measurement unit is single, so that the design and operation of each span time measurement unit are relatively simple.

[0089] It should be noted that when the second span time measurement unit 42 performs measurement, the comparator 50 performs a non-zero comparison and outputs a non-zero comparison pulse signal; when the third span time measurement unit 43 performs measurement, the comparator 50 first performs a non-zero comparison and outputs a non-zero comparison pulse, and then the comparator 50 switches to performing a zero-crossing comparison and outputs a zero-crossing comparison pulse signal.

[0090] In addition, in the embodiments of the present application, Figure 1 As shown, the reference voltage generating unit 60 is electrically connected to the control module 10 and the comparator 50 respectively, and the reference voltage generating unit 60 is used to provide a comparison reference voltage to the comparator 50, wherein the comparison reference voltage is usually set to a voltage greater than or equal to the zero point voltage value, and can also be set to a voltage less than or equal to the zero point voltage value.

[0091] By setting the reference voltage generating unit 60, the control module 10 can control the reference voltage generating unit 60 to provide the comparison reference voltage to the comparator 50, and the comparator 50 has a comparison reference terminal, and the reference voltage generating unit 60 can be electrically connected to the comparison reference terminal. Once the reference voltage generating unit 60 generates the comparison reference voltage, the comparison reference voltage can be transmitted to the comparison reference terminal of the comparator 50. Once the voltage of the input signal terminal of the comparator 50 is greater than the voltage of the comparison reference terminal, the comparator 50 will compare and output a high level, and once the voltage of the input signal terminal is less than the voltage of the comparison reference terminal, the comparator 50 will compare and output a low level. Since the sound wave received by the receiving transducer is a quasi-sine wave, by configuring the reference voltage generating unit 60 so that the voltage value of the generated comparison reference voltage is between the high peak voltage and the low peak voltage of the quasi-sine wave, the quasi-sine wave transmitted to the signal input terminal of the comparator 50 is compared by the comparator 50 and outputs a rectangular wave pulse. When the comparison reference voltage is equal to the zero point voltage of the comparator 50, the rectangular pulse output by the comparator 50 is a square wave pulse. By providing the reference voltage generating unit 60 , the comparator 50 can compare the voltage at its input signal terminal with the voltage at the comparison reference terminal to determine whether to output a comparison pulse.

[0092] It should be noted that the comparator 50 is electrically connected to the transducer assembly 30, so that the response voltage wave generated by the transducer assembly 30 will be transmitted to the comparator 50, and the comparator 50 will compare the voltage of the response voltage wave with the voltage of the comparison reference end. If the voltage of the response voltage wave is greater than the voltage of the comparison reference end, the comparator 50 outputs a high level, and if the voltage of the response voltage wave is less than the voltage of the comparison reference end, the comparator 50 does not output a low level. When the voltage of the comparison reference end is equal to the zero-point voltage of the response voltage wave, the response voltage wave outputs a square wave pulse through zero comparison of the comparator 50. When the voltage of the comparison reference end is greater than or less than the zero-point voltage of the quasi-sine wave, the response voltage wave outputs a rectangular wave pulse through zero comparison of the comparator 50. For the sake of design simplification and simplicity of expression, for non-zero comparison, this application uses the case where the voltage of the comparison reference end is greater than the zero-point voltage of the response voltage wave to illustrate the invention principle.

[0093] It should also be noted that when the comparator 50 performs a non-zero comparison, a comparison reference voltage that is less than the zero-point voltage value of the response voltage wave may also be used, and the embodiments of the present application do not limit this. In addition, those skilled in the art may use a comparison reference voltage according to actual needs, for example, using a comparison reference voltage that is less than the zero-point voltage value, or, for another example, using a comparison reference voltage that is greater than the zero-point voltage value. The embodiments of the present application do not limit this.

[0094] In addition, in the embodiment of the present application, the response voltage wave group transmitted to the comparator 50 can be transmitted to the span time measurement module 40, and the control module 10 controls the reference voltage generating unit 60 to provide the comparator 50 with a comparison reference voltage greater than the zero-point voltage value, so that the comparator 50 performs a non-zero comparison on the response voltage wave group. When a response voltage wave higher than the comparison reference voltage is compared by the comparator, the comparator 50 outputs a non-zero comparison pulse signal. After one or more non-zero comparison pulse signals are output, the control module 10 controls the reference voltage generating unit 60 to provide the comparator 50 with a comparison reference voltage equal to the zero-point voltage value, so that the comparator 50 performs a zero-crossing comparison on the response voltage wave group and outputs multiple zero-crossing comparison pulse signals until the measurement process ends.

[0095] Since the comparator 50 is electrically connected to the transducer assembly 30, the transducer assembly 30 can transmit the generated response voltage wave group to the comparator 50, and the comparator 50 is also electrically connected to the reference voltage generating unit 60, the control module 10 can control the reference voltage generating unit 60 to provide the comparator 50 with a comparison reference voltage greater than the zero-point voltage value of the compared response voltage wave group, so that the comparator 50 will perform a non-zero comparison on the response voltage wave group, and the response voltage wave higher than the comparison reference voltage will output a non-zero comparison pulse signal after the non-zero comparison of the comparator 50, and after the comparator 50 outputs one or more non-zero comparison pulse signals, the control module 10 controls the reference voltage generating unit 60 to provide the comparator 50 with a comparison reference voltage equal to the zero-point voltage value of the compared response voltage wave group, so that the comparator 50 performs a zero-crossing comparison on the response voltage wave group, and the response voltage wave higher than the comparison reference voltage will output a zero-crossing comparison pulse signal after the zero-crossing comparison of the comparator 50, until the measurement of the flight span time of this acoustic wave group flight event is completed. That is, the comparator 50 can have a zero-crossing comparison function and a non-zero comparison function, so that only one comparator 50 is used to complete the identification of the arrival of the response wave for the acoustic wave flyby event and the measurement of the flyby time, thereby saving the number of comparators 50 and reducing costs.

[0096] In addition, in some embodiments, Figure 1 As shown, the device for measuring the acoustic wave flight time may also include a pulse counting unit 70; the pulse counting unit 70 is electrically connected to the control module 10 and the comparator 50 respectively, and the pulse counting unit 70 is used to count the number of comparison pulse signals transmitted to the pulse counting unit 70, and transmit the counted number of comparison pulse signals to the control module 10 or to the span time measurement module 40, so as to trigger the span time measurement module to stop measuring.

[0097] By setting the pulse counting unit 70, the pulse counting unit 70 can transmit the counted number of pulses to the control module 10, so that the control module 10 can determine whether the reference comparison voltage provided by the reference voltage generating unit 60 to the comparator 50 is appropriate, whether the current excitation response wave group measurement overflows, and whether the span time measurement module should stop measuring based on the number of pulses transmitted by the pulse counting unit 70 and the initial number of pulses emitted by the pulse emitting unit 20.

[0098] In addition, in some embodiments, the span time measurement module 40 is used to count the number of comparison pulse signals transmitted to the span time measurement module 40, and transmit the counted number of comparison pulse signals to the control module 10. Through such a setting, it is equivalent to counting the comparison pulse signal through the span time measurement module 40, thereby eliminating the need for an independent pulse counting circuit, simplifying the circuit structure of the device, and facilitating the integration of the device.

[0099] It should be noted that the span time measurement module 40 can be implemented by a TDC chip.

[0100] In addition, in the embodiment of the present application, the measuring device of the acoustic wave transit time may further include a measuring tube 110, the transducer assembly 30 includes a first transducer 31 and a second transducer 32, the first transducer 31 and the second transducer 32 are both arranged at both ends of the measuring tube 110, and a fluid may flow through the measuring tube 110, so that the fluid in the measuring tube 110 may be measured. The fluid includes but is not limited to gas, liquid, etc.

[0101] In addition, the sound wave flight time measuring device provided by the embodiment of the present application can also perform distance measurement. Specifically, after the transducer assembly 30 emits a sound wave group, the sound wave group will be reflected to the transducer assembly 30 after hitting an obstacle, thereby causing the transducer assembly 30 to generate a response voltage wave group. By measuring the span time from the sound wave group emission event to the transducer assembly 30 generating a response voltage wave group event, combined with the propagation speed of the sound wave in the medium, the distance between the obstacle and the sound wave flight time measuring device can be easily determined. The medium for propagating sound waves can be a fluid or a solid.

[0102] It should be noted that, in the present application, sound waves may include ultrasonic waves, sound waves audible to human ears (i.e., conventional sound waves), and infrasound waves. Those skilled in the art may determine the type of sound waves of the measuring device according to the requirements of specific application scenarios, and the present application does not limit this.

[0103] In addition, in some embodiments, Figure 1 As shown, the device for measuring the acoustic wave flight time may also include an analog gate 80; the pulse generating unit 20 is connected to the analog gate 80, the analog gate 80 is electrically connected to the transducer assembly 30, and the analog gate 80 is electrically connected to the comparator 50. The analog gate 80 may select which input signal can be conducted and transmitted, so that the excitation voltage wave group corresponding to the initial pulse group emitted by the pulse generating unit 20 is transmitted to the comparator 50, or the response voltage wave group generated by the transducer assembly 30 is transmitted to the comparator 50.

[0104] Among them, the analog gate 80 can be configured to switch the input signal source that is turned on, so that when the excitation voltage wave group corresponding to the initial pulse group emitted by the pulse generating unit 20 is transmitted to the analog gate 80, the analog gate 80 can be configured so that the excitation voltage wave group is turned on, and then the excitation voltage wave group is transmitted to the fly-time measurement module 40, which is equivalent to the initial pulse group being transmitted to the fly-time measurement module 40, so that the initial pulse group can trigger the span time measurement module 40 to start the span time measurement count. Once the initial pulse group is partially or completely transmitted, the analog gate 80 can be configured to disconnect the path for transmitting the initial pulse group, so that the excitation voltage wave group cannot pass through the analog gate 80, and thus cannot be continuously transmitted to the fly-time measurement unit. The analog gate 80 can be configured to conduct the path of the response voltage wave group generated by the transducer assembly 30, so that the response voltage wave group can be continuously transmitted to the comparator 50, and then the span time measurement module 40 counts, samples and stores the span time of the target edge of the comparison output pulse corresponding to the response voltage wave group, so as to determine the flight time of the sound wave group.

[0105] It should be noted that the analog gate 80 is electrically connected to the response transducer and may also be electrically connected to the transmission transducer.

[0106] It should also be noted that, based on the functions of the analog gate 80 in the embodiment of the present application, a circuit that implements the same functions of the analog gate 80 using basic circuits such as analog switches can also be derived, and those skilled in the art can flexibly set it according to the needs of the actual device and the feasibility of various basic circuits. This application does not limit this.

[0107] In addition, in the embodiments of the present application, Figure 1 As shown, the control module 10 may include an integrated control unit 102 and a controller 101, the controller 101 may be a host computer or a central processing unit, the integrated control unit 102 is connected to the bus interface, and the bus interface is connected to the controller 101, thereby forming the control module 10. Among them, the controller 101 can send instructions to the integrated control unit 102 through the bus interface, and the integrated control unit 102 can control other components. Of course, other components can also be connected to the bus interface through the connection bus, so that the controller 101 directly controls other components, and other components refer to components that are electrically connected to the control module 10 and controlled by the control module 10. For example, other components include a pulse generating unit 20.

[0108] The embodiment of the present application provides a method for measuring the span time of an acoustic wave, and the method for measuring the span time of an acoustic wave is applied to the device for measuring the flight time of an acoustic wave in any of the above embodiments, such as Figure 8 As shown, the measurement method includes:

[0109] Step 701: Determine the number of selected comparison pulses.

[0110] Among them, in some implementations, the comparator of the span time measurement unit operates in a non-zero ratio mode; the implementation method of step 701 can be: measuring the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal output by the comparator after non-zero comparison of the response voltage wave group, so as to determine the span time from the leading edge to the trailing edge of the comparison pulse signal in combination with the counting resolution; the wave group composed of the response voltage waves corresponding to all non-zero comparison output pulses before the span time starts to decrease is the selected response voltage wave group, and the comparison pulses corresponding to the selected response voltage wave group are all selected comparison pulses, so as to determine the number of selected comparison pulses.

[0111] When determining the number of selected comparison pulses, the span time measurement module can be placed in the first mode, where the comparator performs a non-zero comparison.

[0112] Step 702: Based on the number of selected comparison pulses, a reference span time of the acoustic wave transit time of the acoustic wave group is measured, thereby determining the initial acoustic wave transit time, wherein the reference span time is the span time of the target edge of the selected selected pulse signal relative to the target edge of the selected initial pulse signal.

[0113] Among them, when the selected selection pulse signal is the last one among the selection pulse signals and the selected initial pulse signal is the first one of the initial pulse signals, at this time, the reference span time is the span time of the leading edge of the last selection pulse signal relative to the leading edge of the first initial pulse signal, or the reference span time is the span time of the trailing edge of the last selection pulse signal relative to the trailing edge of the first initial pulse signal.

[0114] Among them, after determining the number of selected comparison pulses, the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator of the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group is measured, so that the span time can be determined. Specifically, the count value of the measured span time can be multiplied by the counting resolution of the span time measurement module 40 to determine the span time, and then the initial sound wave flight time is determined.

[0115] The initial acoustic wave transit time can be determined by the following method:

[0116] Initial acoustic wave flight time = reference span time - pulse period x(N-C) of initial pulse group + pulse period x(LD) of initial pulse group;

[0117] Among them, N represents the number of pulses in the initial pulse group, L represents the number of selected comparison pulses, D represents that the Dth selected pulse in the selected comparison pulse is selected, and C represents that the Cth initial pulse signal in the initial pulse signal is selected.

[0118] In addition, when the Dth selected pulse in the selected comparison pulse is selected, C represents that the Cth initial pulse signal in the initial pulse signal is selected, at this time, the reference span time is the span time of the leading edge of the Dth selected pulse signal relative to the leading edge of the Cth initial pulse signal, or the reference span time is the span time of the trailing edge of the Dth selected pulse signal relative to the trailing edge of the Cth initial pulse signal:

[0119] In addition, when the selected measurement pulse signal is the last one among the measurement pulse signals, and the selected initial pulse signal is the first one among the initial pulse signals, that is, D is equal to L and C is equal to 1, at this time, the reference span time is the span time of the leading edge of the last measurement pulse signal relative to the leading edge of the first initial pulse signal, or the reference span time is the span time of the trailing edge of the last measurement pulse signal relative to the trailing edge of the first initial pulse signal;

[0120] The initial acoustic wave transit time is determined as follows:

[0121] The initial acoustic wave flight time = reference span time - the pulse period x(N-1) of the initial pulse group.

[0122] Or various equivalent forms of the above methods are also acceptable, and this application does not limit them.

[0123] Of course, the reference span time of this step can be selected as the span time of the leading edge / trailing edge of any zero-crossing comparison pulse signal in the selected pulse signal relative to the leading edge / trailing edge of any initial pulse signal. This application is not limited to this. The algorithm for determining the initial sound wave flight time can be simply adjusted accordingly according to the principles of the present invention. For the sake of design simplicity and simplicity of expression, this application uses the reference span time selected as the span time of the leading edge of the last zero-crossing comparison pulse signal in the selected pulse signal relative to the leading edge of the first initial pulse signal to illustrate the principles of this application.

[0124] Step 703: Determine the number of selection and comparison pulses again. If the number of selection and comparison pulses measured twice is the same, the initial acoustic wave flight time is used as the effective acoustic wave flight time. If the number of selection and comparison pulses measured twice is different, redetermine the number of selection and comparison pulses, and remeasure and determine the initial acoustic wave flight time until the number of selection and comparison pulses measured twice is the same.

[0125] In addition, in some implementations, the method for measuring the acoustic wave span time may further include: detecting whether the initial acoustic wave flight time is valid.

[0126] In addition, in some implementations, the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by zero comparison of at least two consecutive voltage waves in the selected response voltage wave group corresponding to the acoustic wave flying is measured relative to the target edge of the same target pulse signal in the initial pulse group, and the corresponding span time is determined to obtain the corresponding adjacent span times of at least two adjacent zero-crossing comparison pulse signals; the implementation method for detecting whether the initial acoustic wave flying time is valid can be: subtracting two adjacent span times to obtain the time difference of adjacent span times; comparing the time difference of adjacent span times with the pulse period of the pulse emitted by the pulse generating unit, if the difference between the time difference of adjacent span times and the pulse period of the emitted pulse is within the preset difference range, then the two adjacent span times are valid, and the corresponding initial acoustic wave flying time is valid; if the difference between the time difference of adjacent span times and the pulse period of the emitted pulse is outside the preset difference range, then the two adjacent span times are invalid, and the corresponding initial acoustic wave flying time is invalid.

[0127] An embodiment of the present application provides a device, which includes the device for measuring the acoustic wave transit time in any of the above embodiments.

[0128] It should be noted that the equipment in the embodiments of the present application includes but is not limited to vehicles, ships, submarines, water meters, heat meters, gas meters, oil meters, flow meters, etc.

[0129] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" 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 application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0130] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A device for measuring the acoustic wave transit time, characterized in that: The acoustic wave flight time measuring device comprises: a control module, a pulse generating unit, a transducer assembly, a span time measuring module, a reference voltage generating unit and a comparator; The span time measurement module and the pulse generating unit are both electrically connected to the control module; the pulse generating unit is electrically connected to the transducer assembly and the span time measurement module respectively, the transducer assembly is electrically connected to the comparator, the comparator is electrically connected to the span time measurement module, and the transducer assembly is used to generate and transmit a sound wave group, and / or receive a sound wave group; The pulse generating unit is used to generate and output a periodic initial pulse group, the transducer assembly is used to generate and transmit an acoustic wave group, and the transducer assembly is also used to generate a response voltage wave group when receiving the acoustic wave group, and the response voltage wave group can be transmitted to the comparator; The reference voltage generating unit is electrically connected to the control module and the comparator, and the reference voltage generating unit can generate a zero voltage or a non-zero voltage and output it to the comparator, so that the comparator performs a zero-crossing comparison and outputs a zero-crossing comparison pulse signal, or the comparator performs a non-zero comparison and outputs a non-zero comparison pulse signal; The comparator transmits the comparison pulse signal to the span time measurement module, and the comparison pulse signal includes a zero-crossing comparison pulse signal or a non-zero comparison pulse signal. The span time measurement module is used to measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time, and / or to measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator for the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group to determine the span time, and then determine the sound wave flight time of the sound wave group. The selected response voltage wave group is: when the comparator works in the non-zero comparison mode, among the multiple non-zero comparison pulse signals output by the comparator for the response voltage wave group, the response voltage waves corresponding to all non-zero comparison pulse signals before the span time from the leading edge to the trailing edge of the non-zero comparison pulse signal begins to decrease are the selected response voltage waves, and the wave group composed of all the selected response voltage waves is the selected response voltage wave group.

2. The device for measuring the acoustic wave transit time according to claim 1, characterized in that: The span time measurement module includes a first span time measurement unit, the first span time measurement unit is electrically connected to the comparator and the pulse generation unit respectively, the first span time measurement unit has a first mode and a second mode, and the first span time measurement unit can be switched between the first mode and the second mode; When the first span time measurement unit is in the first mode, the first span time measurement unit is used to measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time; When the first span time measurement unit is in the second mode, the first span time measurement unit is used to measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator of the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group, so as to determine the span time, and then determine the sound wave flight time of the sound wave group.

3. The device for measuring the acoustic wave transit time according to claim 2, characterized in that: The comparison pulse signal output by the comparator corresponding to the selected response voltage wave is recorded as the selected comparison pulse signal. When the first span time measurement unit is in the second mode, during the flight time measurement process of the acoustic wave group flight, the comparator first operates in the non-zero comparison mode, first performs a non-zero comparison on the response voltage wave group to output one or more non-zero comparison pulse signals, and then the comparator switches to the zero-crossing comparison mode, and then performs a zero-crossing comparison on the response voltage wave group to output multiple zero-crossing comparison pulse signals. The first span time measurement unit is used to: perform time counting sampling on the span time of the target edge of one or more zero-crossing comparison pulse signals after the last non-zero comparison pulse signal among the multiple selected comparison pulse signals corresponding to the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group, so as to obtain and cache one or more span time count values, so as to determine the span time, and then determine the acoustic wave flight time of the acoustic wave group; Or, the first span time measurement unit is used to: perform time counting sampling on the span time of the target edge of each zero-crossing comparison pulse signal after the last non-zero comparison pulse signal among the multiple selected comparison pulse signals corresponding to the selected response voltage wave group relative to the target edge of the selected pulse signal in the initial pulse group, until the measurement end mark arrives, or the number of the comparison pulse signals reaches a preset number threshold, so as to determine the span time, and then determine the sound wave flight time of the sound wave group; and cache the count value of each sampled span time, wherein, after the counting storage unit in the first span time measurement unit is full of data, when the count value of the new span time enters the counting storage unit, the span time count value that previously entered the counting storage unit overflows, so that the span time count value that later enters the counting storage unit can be cached.

4. The device for measuring the acoustic wave transit time according to claim 1, characterized in that: The span time measurement module includes a second span time measurement unit and a third span time measurement unit, the second span time measurement unit and the third span time measurement unit are both electrically connected to the comparator, and the pulse generation unit is electrically connected to the third span time measurement unit; The second span time measurement unit is used to measure the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal to determine the span time; The third span time measurement unit is used to measure the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by the comparator after the selected response voltage wave group is compared with the target edge of the selected pulse signal in the initial pulse group, so as to determine the span time, and then determine the sound wave flight time of the sound wave group.

5. The device for measuring the acoustic wave transit time according to claim 1, characterized in that: The response voltage wave group transmitted to the comparator can be transmitted to the span time measurement module. The control module controls the reference voltage generating unit to provide the comparator with a comparison reference voltage greater than the zero-point voltage value, so that the comparator performs a non-zero comparison on the response voltage wave group. When a response voltage wave higher than the comparison reference voltage is compared by the comparator, the comparator outputs a non-zero comparison pulse signal. After one or more non-zero comparison pulse signals are output, the control module controls the reference voltage generating unit to provide the comparator with a comparison reference voltage equal to the zero-point voltage value, so that the comparator performs a zero-crossing comparison on the response voltage wave group and outputs one or more zero-crossing comparison pulse signals until the measurement process ends.

6. The device for measuring the acoustic wave transit time according to claim 1, characterized in that: The device for measuring the acoustic wave transit time also includes a pulse counting unit; The pulse counting unit is electrically connected to the control module and the comparator respectively, and is used to count the number of comparison pulse signals transmitted to the pulse counting unit, and transmit the counted number of comparison pulse signals to the control module.

7. The device for measuring the acoustic wave transit time according to claim 1, characterized in that: The span time measurement module is used to count the number of comparison pulse signals transmitted to the span time measurement module, and transmit the counted number of comparison pulse signals to the control module.

8. The device for measuring the acoustic wave transit time according to claim 1, characterized in that: The device for measuring the acoustic wave flight time also includes an analog gate; The analog gate is electrically connected to the pulse generating unit and the transducer assembly, and the analog gate is electrically connected to the comparator. The analog gate is switched on so that the excitation voltage wave group corresponding to the initial pulse group emitted by the pulse generating unit is transmitted to the comparator, or the response voltage wave group generated by the transducer assembly is transmitted to the comparator.

9. The device for measuring the acoustic wave transit time according to claim 1, characterized in that: The device for measuring the acoustic wave transit time further comprises a first output buffer and a second output buffer, and the transducer assembly comprises a first transducer and a second transducer; The first output buffer is electrically connected to the pulse generating unit and the first transducer respectively, and the second output buffer is electrically connected to the pulse generating unit and the second transducer respectively; One of the first transducer and the second transducer serves as an excitation transducer, and the other serves as a response transducer. When the first output buffer is configured as an output state and the second output buffer is configured as a cut-off state, the first output buffer provides an excitation voltage and a current to the first transducer, so that the first transducer serves as an excitation transducer and the second transducer serves as a response transducer. The first transducer generates and transmits a sound wave group, the second transducer receives the sound wave group and generates a response voltage wave group, and the response transducer is electrically connected to the comparator. When the second output buffer is configured as an output state and the first output buffer is configured as a cut-off state, the second output buffer provides an excitation voltage and a current to the second transducer, so that the second transducer serves as an excitation transducer and the first transducer serves as a response transducer. The second transducer generates and transmits a sound wave group, the first transducer receives the sound wave group and generates a response voltage wave group, and the response transducer is electrically connected to the comparator.

10. A method for measuring the span time of a sound wave, characterized in that: Applicable to the device for measuring the acoustic wave transit time as described in any one of claims 1 to 9, the measuring method comprises: Determine the number of selected comparison pulses; Based on the number of selected comparison pulses, a reference span time of the acoustic wave flight time of the acoustic wave group is measured, and then the initial acoustic wave flight time is determined, wherein the reference span time is the span time of the target edge of the selected selected pulse signal relative to the target edge of the selected initial pulse signal; Determine the number of selection and comparison pulses again. If the number of selection and comparison pulses measured twice is the same, the initial acoustic wave flight time is used as the effective acoustic wave flight time. If the number of selection and comparison pulses measured twice is different, redetermine the number of selection and comparison pulses, and remeasure and determine the initial acoustic wave flight time until the number of selection and comparison pulses measured twice is the same.

11. The method for measuring the sound wave span time according to claim 10, characterized in that: The method for measuring the sound wave span time also includes: detecting whether the initial sound wave flight time is valid.

12. The method for measuring the sound wave span time according to claim 11, characterized in that: Measure and obtain the count value of the span time of the target edge of the zero-crossing comparison pulse signal output by zero comparison of at least two consecutive voltage waves in the selected response voltage wave group corresponding to the acoustic wave flying relative to the target edge of the same target pulse signal in the initial pulse group, and determine the corresponding span time to obtain the corresponding adjacent span time of at least two adjacent zero-crossing comparison pulse signals; The detecting whether the initial acoustic wave flight time is valid comprises: Subtract two adjacent span times to obtain the time difference between the adjacent span times; compare the obtained time difference with the pulse period of the pulse emitted by the pulse generating unit. If the time difference between the adjacent span times and the difference between the pulse period are within a preset difference range, then both of the two adjacent span times are valid, and the corresponding initial sound wave flight time is valid; if the time difference between the adjacent span times and the difference between the pulse period are outside the preset difference range, then both of the two adjacent span times are invalid, and the corresponding initial sound wave flight time is invalid.

13. The method for measuring the sound wave span time according to claim 10, characterized in that: The comparator operates in a non-zero comparison mode; The step of determining the number of selected comparison pulses comprises: Measuring the count value of the span time from the leading edge to the trailing edge of the comparison pulse signal output by the comparator after the response voltage wave group is compared with the non-zero value, so as to determine the span time from the leading edge to the trailing edge of the comparison pulse signal in combination with the counting resolution; The wave group consisting of the response voltage waves corresponding to all non-zero comparison output pulses before the span time starts to decrease is the selected response voltage wave group, and the comparison pulses corresponding to the selected response voltage wave group are all selected comparison pulses to determine the number of selected comparison pulses.

14. The method for measuring the sound wave span time according to claim 10, characterized in that: The method of measuring the reference span time of the acoustic wave transit time of the acoustic wave group based on the selected comparison pulse quantity, and then determining the initial acoustic wave transit time, comprises: Initial acoustic wave flight time = reference span time - pulse period x(N-C) of initial pulse group + pulse period x(LD) of initial pulse group; Among them, N represents the number of pulses in the initial pulse group, L represents the number of the selected comparison pulses, D represents that the Dth selected comparison pulse is selected, and C represents that the Cth initial pulse signal is selected in the initial pulse signal.

15. A device, characterized in that The device comprises the device for measuring the acoustic wave transit time according to any one of claims 1-9.

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