Phase flip point detection circuit of ultrasonic receiving waveform envelope
By designing a phase flip point detection circuit for the ultrasonic receiving waveform envelope, the zero crossing detection module is used to accurately judge the arrival time of the ultrasonic receiving signal, which solves the problem of low ultrasonic flow measurement accuracy and improves the measurement accuracy.
Patent Information
- Application Number
- CN202411373317.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2024-12-10
AI Technical Summary
Due to the influence of noise, the existing time-difference ultrasonic flow measurement methods cause the ultrasonic reception signal to shift to the mark point, which in turn affects the ultrasonic time of flight measurement accuracy, resulting in the ultrasonic flow measurement accuracy being low.
A phase flip point detection circuit of ultrasonic receiving waveform envelope is designed, including ultrasonic receiving signal amplification module, bandpass filter amplification module, detection module, low-pass filter module, differential module and zero crossing detection module, through ultrasonic receiving waves The phase flip point of the envelope trough is detected to accurately judge the arrival time of the ultrasonic received signal.
The ultrasonic flight time measurement accuracy is improved, effectively solving the problem of low ultrasonic flow measurement accuracy.
Smart Images
Figure CN119104126A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of ultrasonic flow measurement, and in particular relates to a phase reversal point detection circuit of an ultrasonic receiving waveform envelope. Background Art
[0002] Flow measurement is the technical foundation of process industry and national defense construction. The reliability, safety and accuracy of metering data are closely related to the development of national economy, scientific research and industrial technology. Among the existing flow measurement methods, ultrasonic flow measurement is a new flow measurement method. Due to its small pressure loss, no internal moving parts and wide range ratio, it has been gradually applied to the fields of petrochemical, urban water supply and sewage discharge.
[0003] Among them, the time-difference ultrasonic flow measurement method uses the acoustic principle to measure the flow rate of the fluid flowing through the pipeline. During the time-difference ultrasonic flow measurement process, a pair of ultrasonic receiving transducers are installed on the pipeline wall. The ultrasonic excitation circuit applies an excitation signal to the ultrasonic transmitting transducer to generate ultrasonic waves. The ultrasonic receiving transducer receives the ultrasonic signal and converts it into an electrical signal. The ultrasonic measurement circuit records the time from ultrasonic emission to reception. The propagation speed of the ultrasonic wave changes under the conditions of downstream and upstream flow. The fluid velocity is measured using the time difference under the conditions of downstream and upstream flow.
[0004] When the ultrasonic receiving signal is a sinusoidal signal, a threshold comparison circuit is usually used to detect the ultrasonic receiving signal. When the amplitude of the ultrasonic receiving signal exceeds a certain threshold, the threshold comparison circuit outputs a level signal as the mark point of the ultrasonic receiving signal arrival, and the trigger time timing module stops timing. However, in actual applications, due to the influence of noise, the amplitude of the received echo will change, the trigger point will also shift, and the mark point of the ultrasonic receiving signal arrival will be advanced or delayed, which will affect the measurement accuracy of the ultrasonic emission to reception flight time, resulting in low accuracy of ultrasonic flow measurement.
[0005] In summary, the existing time-difference ultrasonic flow measurement method has the problem of low ultrasonic flow measurement accuracy. Summary of the invention
[0006] The object of the present invention is to provide a phase reversal point detection circuit for an ultrasonic receiving waveform envelope, so as to solve the problem of low ultrasonic flow measurement accuracy in the prior art.
[0007] In order to achieve the above object, the present invention adopts the following technical solution: In a first aspect, the present invention provides a phase reversal point detection circuit of an ultrasonic receiving waveform envelope, the detection circuit comprising an ultrasonic receiving signal amplification module, a bandpass filter amplification module, a detection module, a low-pass filter module, a differentiation module and a zero-crossing point detection module; The ultrasonic receiving signal amplification module is used to amplify the signal received by the ultrasonic receiving transducer; the bandpass filtering module is used to perform bandpass filtering on the signal obtained after amplification by the ultrasonic receiving signal amplification module; the detection module is used to detect the signal obtained after bandpass filtering by the bandpass filtering module; the low-pass filtering module is used to filter out the high-frequency harmonic components of the signal obtained after detection by the detection module; the differentiation module is used to differentiate the signal obtained after filtering by the low-pass filtering module to obtain the slope of the smooth waveform; the zero-crossing detection module is used to detect the phase reversal point of the trough of the ultrasonic receiving wave envelope.
[0008] A further improvement of the present invention is that the ultrasonic receiving signal amplification module includes a first operational amplifier, a fixed resistor R1, a fixed resistor R2, a fixed resistor R3, a fixed resistor R4, a fixed capacitor C1, a fixed capacitor C2, a fixed capacitor C3, a fixed capacitor C4 and an ultrasonic receiving wave transducer; The reverse input terminal of the first operational amplifier is connected to one end of the fixed-value capacitor C2, one end of the fixed-value capacitor C2 is also connected to one end of the fixed-value resistor R3, the other end of the fixed-value resistor R3 is grounded, and the other end of the fixed-value capacitor C2 is connected to one end of the fixed-value resistor R1; the same-direction input terminal of the first operational amplifier is connected to one end of the fixed-value capacitor C1, one end of the fixed-value capacitor C1 is also connected to one end of the fixed-value resistor R2, the other end of the fixed-value resistor R2 is grounded, and the other end of the fixed-value capacitor C1 is connected to the other end of the fixed-value resistor R1; the RG1 pin of the first operational amplifier is connected to one end of the fixed-value resistor R4, and the RG2 pin of the instrument amplifier is connected to the other end of the fixed-value resistor R4; the positive and negative poles of the power supply of the first operational amplifier are connected to the power supply, one end of the fixed-value capacitor C4 and one end of the fixed-value capacitor C3 are respectively connected to the positive and negative poles of the power supply of the first operational amplifier, the other end of the fixed-value capacitor C4 and the other end of the fixed-value capacitor C3 are both grounded, and the first pin and the second pin of the ultrasonic receiving wave transducer are connected to the two ends of the fixed-value resistor R1.
[0009] A further improvement of the present invention is that the model of the first operational amplifier is INA217.
[0010] A further improvement of the present invention is that the bandpass filter amplification module includes a second operational amplifier, a fixed resistor R5, a fixed resistor R6, a fixed resistor R7, a fixed resistor R8, a fixed resistor R9, a fixed capacitor C5, a fixed capacitor C6, a fixed capacitor C7 and a fixed capacitor C8; The OUT pin of the second operational amplifier is connected to one end of the fixed resistor R7 and one end of the fixed resistor R9, the other end of the fixed resistor R7 is connected to one end of the fixed resistor R5, one end of the fixed capacitor C6 and one end of the fixed capacitor C5, the other end of the fixed resistor R9 is connected to one end of the fixed resistor R8, one end of the fixed resistor R8 is also connected to the reverse input end of the second operational amplifier, the other end of the fixed resistor R5 is connected to the ultrasonic receiving signal amplification module, the other end of the fixed capacitor C6 is connected to one end of the fixed resistor R6, the other end of the fixed capacitor C6 is also connected to the same direction input end of the second operational amplifier, the other end of the fixed resistor R6 and the other end of the fixed capacitor C5 are both connected to the other end of the fixed resistor R8; the positive and negative poles of the power supply of the second operational amplifier are connected to the power supply, one end of the fixed capacitor C8 and one end of the fixed capacitor C7 are respectively connected to the positive and negative poles of the power supply of the second operational amplifier, and the other end of the fixed capacitor C8 and the other end of the fixed capacitor C7 are both grounded.
[0011] A further improvement of the present invention is that the detection module includes a fixed resistor R10 and a fixed capacitor C9 connected in parallel, which are connected in series with a detection diode after being connected in parallel, one end of the fixed resistor R10 and the fixed capacitor C9 connected in parallel is grounded, and the other end of the fixed resistor R10 and the fixed capacitor C9 connected in parallel is connected to the cathode of the detection diode, and the other end of the fixed resistor R10 and the fixed capacitor C9 connected in parallel is also connected to the low-pass filtering module, and the anode of the detection diode is connected to the band-pass filtering amplification module.
[0012] A further improvement of the present invention is that the detector diode is of model IN60.
[0013] A further improvement of the present invention is that the low-pass filter module includes a third operational amplifier, a fixed resistor R11, a fixed resistor R12, a fixed capacitor C10, a fixed capacitor C11, a fixed capacitor C12 and a fixed capacitor C13; The same-direction input terminal of the third operational amplifier is connected to one end of the fixed resistor R12, the other end of the fixed resistor R12 is connected to one end of the fixed resistor R11, and the other end of the fixed resistor R11 is connected to the detection module; the same-direction input terminal of the third operational amplifier is also connected to one end of the fixed capacitor C10, and the other end of the fixed capacitor C10 is grounded; the reverse input terminal of the third operational amplifier is connected to the OUT pin of the third operational amplifier, the reverse input terminal of the third operational amplifier is also connected to one end of the fixed capacitor C11, and the other end of the fixed capacitor C11 is connected to the other end of the fixed resistor R12; the positive and negative poles of the power supply of the third operational amplifier are connected to the power supply, one end of the fixed capacitor C12 and one end of the fixed capacitor C13 are respectively connected to the positive and negative poles of the power supply of the third operational amplifier, and the other end of the fixed capacitor C12 and the other end of the fixed capacitor C13 are both grounded.
[0014] A further improvement of the present invention is that the differential module includes a fourth operational amplifier, a fixed resistor R13, a fixed resistor R14, a fixed resistor R15, a fixed capacitor C14, a fixed capacitor C15 and a fixed capacitor C16; The reverse input terminal of the fourth operational amplifier is connected to one end of the fixed resistor R14, the other end of the fixed resistor R14 is connected to the OUT pin of the fourth operational amplifier, the reverse input terminal of the fourth operational amplifier is also connected to one end of the fixed capacitor C14, one end of the fixed capacitor C14 is connected to one end of the fixed resistor R13, and the other end of the fixed resistor R13 is connected to the low-pass filter module; the same-direction input terminal of the fourth operational amplifier is connected to one end of the fixed resistor R15, and the other end of the fixed resistor R15 is grounded; the positive and negative poles of the power supply of the fourth operational amplifier are connected to the power supply, one end of the fixed capacitor C15 and one end of the fixed capacitor C16 are respectively connected to the positive and negative poles of the power supply of the fourth operational amplifier, and the other end of the fixed capacitor C15 and the other end of the fixed capacitor C16 are both grounded.
[0015] A further improvement of the present invention is that the zero-crossing detection module includes a fifth operational amplifier, a diode, a fixed resistor R16, a fixed resistor R17, a fixed resistor R18, a fixed resistor R19, a fixed resistor 20, a fixed resistor R21, a fixed resistor R22 and a fixed capacitor C17; The same-direction input terminal of the fifth operational amplifier is connected to one end of the fixed resistor R21, and the other end of the fixed resistor R21 is grounded; the reverse input terminal of the fifth operational amplifier is connected to one end of the fixed resistor R17, and the other end of the fixed resistor R17 is connected to one end of the fixed resistor R16, and the other end of the fixed resistor R17 is also connected to the cathode of the diode, and the anode of the diode is grounded, and the other end of the fixed resistor R16 is connected to the differential module; the 1OUT pin of the fifth operational amplifier is connected to one end of the fixed resistor R20, and the fixed resistor R2 The other end of 0 is connected to one end of a fixed resistor R19, and the other end of the fixed resistor R19 is connected to a power supply; the other end of the fixed resistor R19 is also connected to one end of a fixed resistor R18, and the other end of the fixed resistor R18 is connected to one end of a fixed resistor R17; the 1OUT pin of the fifth operational amplifier is also connected to one end of a fixed resistor R22, and the other end of the fixed resistor R22 is connected to the other end of the fixed resistor R19; the VCC pin of the fifth operational amplifier is connected to one end of a fixed capacitor C17, and the other end of the fixed capacitor C17 is grounded.
[0016] A further improvement of the present invention is that the fifth operational amplifier adopts a model of LM393, and the diode adopts a model of IN914.
[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention is an improved invention. Compared with the existing time-difference ultrasonic flow measurement method, the phase reversal point detection circuit of the ultrasonic receiving waveform envelope proposed by the present invention designs a zero-crossing point detection module for detecting the phase reversal point of the ultrasonic receiving wave envelope trough. By detecting the phase reversal point of the ultrasonic receiving wave envelope trough, the arrival time of the ultrasonic receiving signal can be accurately determined, thereby improving the measurement accuracy of the ultrasonic flight time, and effectively solving the problem of low ultrasonic flow measurement accuracy in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the phase reversal point detection principle of the ultrasonic receiving waveform envelope of the present invention; Figure 2 It is a block diagram of the phase reversal point detection principle of the ultrasonic receiving waveform envelope of the present invention; Figure 3a It is a circuit diagram of an ultrasonic receiving signal amplifying module in a phase reversal point detection circuit of an ultrasonic receiving waveform envelope of the present invention; Figure 3b It is a circuit diagram of a bandpass filter amplification module in a phase reversal point detection circuit of an ultrasonic receiving waveform envelope of the present invention; Figure 3c It is a circuit diagram of a detection module in a phase reversal point detection circuit of an ultrasonic receiving waveform envelope of the present invention; Figure 3d It is a circuit diagram of a low-pass filter module in a phase reversal point detection circuit of an ultrasonic receiving waveform envelope of the present invention; Figure 3e It is a circuit diagram of a differential module in a phase reversal point detection circuit of an ultrasonic receiving waveform envelope of the present invention; Figure 3f The present invention is a circuit diagram of a zero-crossing point detection module in a phase reversal point detection circuit of an ultrasonic receiving waveform envelope. DETAILED DESCRIPTION
[0019] In order to further understand the content of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.
[0020] The phase reversal point detection circuit of the ultrasonic receiving waveform envelope proposed by the present invention comprises an ultrasonic receiving signal amplification module, a bandpass filter amplification module, a detection module, a low-pass filter module, a differential module and a zero-crossing detection module. The present invention designs the zero-crossing detection module to detect the phase reversal point of the ultrasonic receiving wave envelope trough, accurately determines the arrival time of the ultrasonic receiving signal, and thus improves the measurement accuracy of the ultrasonic flight time. Compared with the prior art, the present invention effectively solves the problem of low ultrasonic flow measurement accuracy in the prior art.
[0021] Embodiment of the phase reversal point detection circuit of the ultrasonic receiving waveform envelope: The schematic diagram of the phase reversal point detection principle of the ultrasonic receiving waveform envelope and the detection principle block diagram of the present invention are as follows: Figure 1 and Figure 2 As shown, this embodiment uses phase modulation technology to drive the ultrasonic transmitting transducer to generate a self-interference transmitting waveform, and the receiving waveform envelope produces a phase flip, that is, the receiving waveform envelope forms a phase flip point, and the pulse width of a series of driving pulses is doubled to form phase flip points before and after the driving pulses. The driving pulses are phase modulated, and the ultrasonic flight time is measured by the time interval between the phase flip points of the ultrasonic driving waveform and the receiving waveform envelope.
[0022] The circuit modules of the phase reversal point detection circuit of the ultrasonic receiving waveform envelope of the present invention are as follows: Figure 3a , Figure 3b , Figure 3c , Figure 3d , Figure 3e and Figure 3f As shown, the technical solution of the present invention is specifically described as follows: The phase reversal point detection circuit of the ultrasonic receiving waveform envelope of the present invention comprises an ultrasonic receiving signal amplification module, a bandpass filtering amplification module, a detection module, a low-pass filtering module, a differentiation module and a zero-crossing point detection module.
[0023] The ultrasonic receiving signal amplification module is used to amplify the signal received by the ultrasonic receiving transducer. The bandpass filtering module is used to perform bandpass filtering on the signal obtained after amplification by the ultrasonic receiving signal amplification module. The detection module is used to detect the signal obtained after bandpass filtering by the bandpass filtering module. The low-pass filtering module is used to filter out the high-frequency harmonic components of the signal obtained after detection by the detection module. The differentiation module is used to differentiate the signal obtained after filtering by the low-pass filtering module to obtain the slope of the smooth waveform. The zero-crossing detection module is used to detect the phase reversal point of the trough of the ultrasonic receiving wave envelope.
[0024] The above modules are described in detail below, where the ultrasonic receiving signal amplification module includes a first operational amplifier (also called U1), a fixed resistor R1, a fixed resistor R2, a fixed resistor R3, a fixed resistor R4, a fixed capacitor C1, a fixed capacitor C2, a fixed capacitor C3, a fixed capacitor C4 and an ultrasonic receiving wave transducer 400SR160, such as Figure 3a shown.
[0025] The reverse input terminal of the first operational amplifier U1 is connected to one end of the fixed value capacitor C2, one end of the fixed value capacitor C2 is also connected to one end of the fixed value resistor R3, the other end of the fixed value resistor R3 is grounded, and the other end of the fixed value capacitor C2 is connected to one end of the fixed value resistor R1. The same direction input terminal of the first operational amplifier U1 is connected to one end of the fixed value capacitor C1, one end of the fixed value capacitor C1 is also connected to one end of the fixed value resistor R2, the other end of the fixed value resistor R2 is grounded, and the other end of the fixed value capacitor C1 is connected to the other end of the fixed value resistor R1. The RG1 pin of the first operational amplifier U1 is connected to one end of the fixed value resistor R4, and the RG2 pin of the first operational amplifier U1 is connected to the other end of the fixed value resistor R4. The positive and negative poles of the power supply of the first operational amplifier U1 are connected to the power supply, one end of the fixed value capacitor C4 and one end of the fixed value capacitor C3 are respectively connected to the positive and negative poles of the power supply of the first operational amplifier U1, and the other end of the fixed value capacitor C4 and the other end of the fixed value capacitor C3 are both grounded. The first pin and the second pin of the ultrasonic receiving wave transducer 400SR160 are connected to both ends of the fixed value resistor R1 for impedance matching. The first operational amplifier U1 in this embodiment adopts the model INA217, and the values of the resistors R1, R2, R3 and R4 are 3.9K, 10K, 10K and 1.11K respectively, and the values of the capacitors C1, C2, C3 and C4 are 0.22uF, 0.22uF, 0.1uF and 0.1uF respectively.
[0026] The bandpass filter amplifier module includes a second operational amplifier (also called U2), a fixed resistor R5, a fixed resistor R6, a fixed resistor R7, a fixed resistor R8, a fixed resistor R9, a fixed capacitor C5, a fixed capacitor C6, a fixed capacitor C7 and a fixed capacitor C8, such as Figure 3b shown.
[0027] The OUT pin of the second operational amplifier U2 is connected to one end of the fixed resistor R7 and one end of the fixed resistor R9, the other end of the fixed resistor R7 is connected to one end of the fixed resistor R5, one end of the fixed capacitor C6 and one end of the fixed capacitor C5, the other end of the fixed resistor R9 is connected to one end of the fixed resistor R8, one end of the fixed resistor R8 is also connected to the reverse input end of the second operational amplifier U2, the other end of the fixed resistor R5 is connected to the ultrasonic receiving signal amplification module, the other end of the fixed capacitor C6 is connected to one end of the fixed resistor R6, the other end of the fixed capacitor C6 is also connected to the same direction input end of the second operational amplifier U2, the other end of the fixed resistor R6 and the other end of the fixed capacitor C5 are both connected to the other end of the fixed resistor R8; the positive and negative poles of the power supply of the second operational amplifier U2 are connected to the power supply, one end of the fixed capacitor C8 and one end of the fixed capacitor C7 are respectively connected to the positive and negative poles of the power supply of the second operational amplifier U2, and the other end of the fixed capacitor C8 and the other end of the fixed capacitor C7 are both grounded. The model of the second operational amplifier U2 in this embodiment is OPA211, the values of resistors R5, R6, R7, R8 and R9 are 33.2K, 5.9K, 3K, 2.49K and 2.49K respectively, and the values of capacitors C5, C6, C7 and C8 are 1nF, 1nF, 0.1uF and 0.1uF respectively.
[0028] The detection module includes a fixed resistor R10 and a fixed capacitor C9 connected in parallel. After the fixed resistor R10 and the fixed capacitor C9 are connected in parallel, they are connected in series with the detection diode VD1. One end of the fixed resistor R10 and the fixed capacitor C9 connected in parallel is grounded, and the other end of the fixed resistor R10 and the fixed capacitor C9 connected in parallel is connected to the negative electrode of the detection diode VD1. The other end of the fixed resistor R10 and the fixed capacitor C9 connected in parallel is also connected to the low-pass filter module. The positive electrode of the detection diode VD1 is connected to the OUT pin of the first operational amplifier U4 of the band-pass filter amplifier module, as shown in FIG. Figure 3c In this embodiment, the detector diode VD1 adopts the model IN60, the resistor R10 has a value of 6K, and the capacitor C9 has a value of 10nF.
[0029] The low-pass filter module includes a third operational amplifier (also called U3), a fixed resistor R11, a fixed resistor R12, a fixed capacitor C10, a fixed capacitor C11, a fixed capacitor C12 and a fixed capacitor C13, such as Figure 3d shown.
[0030] The same-direction input terminal of the third operational amplifier U3 is connected to one end of the fixed resistor R12, the other end of the fixed resistor R12 is connected to one end of the fixed resistor R11, and the other end of the fixed resistor R11 is connected to the detection module. The same-direction input terminal of the third operational amplifier U3 is also connected to one end of the fixed capacitor C10, and the other end of the fixed capacitor C10 is grounded. The reverse input terminal of the third operational amplifier U3 is connected to the OUT pin of the third operational amplifier U3, the reverse input terminal of the third operational amplifier U3 is also connected to one end of the fixed capacitor C11, and the other end of the fixed capacitor C11 is connected to the other end of the fixed resistor R12. The positive and negative poles of the power supply of the third operational amplifier U3 are connected to the power supply, one end of the fixed capacitor C12 and one end of the fixed capacitor C13 are respectively connected to the positive and negative poles of the power supply of the third operational amplifier U3, and the other end of the fixed capacitor C12 and the other end of the fixed capacitor C13 are both grounded. The third operational amplifier U3 of this embodiment adopts the model OPA211, the values of the resistor R11 and the resistor R12 are 1.58K and 2.37K respectively, and the values of the capacitors C10, C11, C12 and C13 are 10nF, 39nF, 0.1uF and 0.1uF respectively.
[0031] The differential module includes a fourth operational amplifier (also called U4), a fixed resistor R13, a fixed resistor R14, a fixed resistor R15, a fixed capacitor C14, a fixed capacitor C15 and a fixed capacitor C16, as shown in FIG. Figure 3e shown.
[0032] The reverse input terminal of the fourth operational amplifier U4 is connected to one end of the fixed resistor R14, the other end of the fixed resistor R14 is connected to the OUT pin of the fourth operational amplifier U4, the reverse input terminal of the fourth operational amplifier U4 is also connected to one end of the fixed capacitor C14, one end of the fixed capacitor C14 is connected to one end of the fixed resistor R13, and the other end of the fixed resistor R13 is connected to the low-pass filter module. The same-direction input terminal of the fourth operational amplifier U4 is connected to one end of the fixed resistor R15, and the other end of the fixed resistor R15 is grounded. The positive and negative poles of the power supply of the fourth operational amplifier U4 are connected to the power supply, one end of the fixed capacitor C15 and one end of the fixed capacitor C16 are respectively connected to the positive and negative poles of the power supply of the fourth operational amplifier U4, and the other end of the fixed capacitor C15 and the other end of the fixed capacitor C16 are both grounded. The operational amplifier U4 of this embodiment adopts the model OPA211, the values of resistors R13, R14 and R15 are 16K (also called 16k), 1K (also called 1k) and 1K (also called 1k) respectively, and the values of capacitors C14, C15 and C16 are all 0.1uF.
[0033] The zero-crossing detection module includes a fifth operational amplifier (also called U5), a diode D1, a fixed resistor R16, a fixed resistor R17, a fixed resistor R18, a fixed resistor R19, a fixed resistor 20, a fixed resistor R21, a fixed resistor R22 and a fixed capacitor C17, as shown in FIG. Figure 3f shown.
[0034] The same-direction input end of the fifth operational amplifier U5 is connected to one end of a fixed resistor R21, and the other end of the fixed resistor R21 is grounded. The reverse input end of the fifth operational amplifier U5 is connected to one end of a fixed resistor R17, and the other end of the fixed resistor R17 is connected to one end of a fixed resistor R16, and the other end of the fixed resistor R17 is also connected to the cathode of a diode D1, and the anode of the diode is grounded, and the other end of the fixed resistor R16 is connected to a differential module. The 1OUT pin of the fifth operational amplifier U5 is connected to one end of a fixed resistor R20, and the other end of the fixed resistor R20 is connected to one end of a fixed resistor R19, and the other end of the fixed resistor R19 is connected to a power supply. The other end of the fixed resistor R19 is also connected to one end of a fixed resistor R18, and the other end of the fixed resistor R18 is connected to one end of a fixed resistor R17. The 1OUT pin of the fifth operational amplifier U5 is also connected to one end of a fixed resistor R22, and the other end of the fixed resistor R22 is connected to the other end of a fixed resistor R19. The VCC pin of the fifth operational amplifier U5 is connected to one end of the fixed value capacitor C17, and the other end of the fixed value capacitor C17 is grounded. In this embodiment, the fifth operational amplifier U5 adopts the model LM393, the diode D1 adopts the model IN914, the resistor R16, the resistor R17, the resistor R18, the resistor R19, the resistor R20, the resistor R21 and the resistor R22 have values of 8.2K (also called 8.2k), 6.8K (also called 6.8k), 220K (also called 220k), 220K (also called 220k), 10M, 15K (also called 15k) and 10K (also called 10k), respectively, and the value of the capacitor C17 is 0.1uF.
[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A phase reversal point detection circuit for an ultrasonic receiving waveform envelope, characterized in that: The detection circuit includes an ultrasonic receiving signal amplification module, a bandpass filter amplification module, a detection module, a low-pass filter module, a differentiation module and a zero-crossing detection module; The ultrasonic receiving signal amplification module is used to amplify the signal received by the ultrasonic receiving transducer; the bandpass filtering module is used to perform bandpass filtering on the signal obtained after amplification by the ultrasonic receiving signal amplification module; the detection module is used to detect the signal obtained after bandpass filtering by the bandpass filtering module; the low-pass filtering module is used to filter out the high-frequency harmonic components of the signal obtained after detection by the detection module; the differentiation module is used to differentiate the signal obtained after filtering by the low-pass filtering module to obtain the slope of the smooth waveform; the zero-crossing detection module is used to detect the phase reversal point of the trough of the ultrasonic receiving wave envelope.
2. The phase reversal point detection circuit of the ultrasonic receiving waveform envelope according to claim 1, characterized in that: The ultrasonic receiving signal amplification module includes a first operational amplifier, a fixed value resistor R1, a fixed value resistor R2, a fixed value resistor R3, a fixed value resistor R4, a fixed value capacitor C1, a fixed value capacitor C2, a fixed value capacitor C3, a fixed value capacitor C4 and an ultrasonic receiving wave transducer; The reverse input terminal of the first operational amplifier is connected to one end of the fixed-value capacitor C2, one end of the fixed-value capacitor C2 is also connected to one end of the fixed-value resistor R3, the other end of the fixed-value resistor R3 is grounded, and the other end of the fixed-value capacitor C2 is connected to one end of the fixed-value resistor R1; the same-direction input terminal of the first operational amplifier is connected to one end of the fixed-value capacitor C1, one end of the fixed-value capacitor C1 is also connected to one end of the fixed-value resistor R2, the other end of the fixed-value resistor R2 is grounded, and the other end of the fixed-value capacitor C1 is connected to the other end of the fixed-value resistor R1; the RG1 pin of the first operational amplifier is connected to one end of the fixed-value resistor R4, and the RG2 pin of the instrument amplifier is connected to the other end of the fixed-value resistor R4; the positive and negative poles of the power supply of the first operational amplifier are connected to the power supply, one end of the fixed-value capacitor C4 and one end of the fixed-value capacitor C3 are respectively connected to the positive and negative poles of the power supply of the first operational amplifier, the other end of the fixed-value capacitor C4 and the other end of the fixed-value capacitor C3 are both grounded, and the first pin and the second pin of the ultrasonic receiving wave transducer are connected to the two ends of the fixed-value resistor R1.
3. The phase reversal point detection circuit of the ultrasonic receiving waveform envelope according to claim 2, characterized in that: The model of the first operational amplifier is INA217.
4. The phase reversal point detection circuit of the ultrasonic receiving waveform envelope according to claim 1, characterized in that: The bandpass filter amplification module includes a second operational amplifier, a fixed resistor R5, a fixed resistor R6, a fixed resistor R7, a fixed resistor R8, a fixed resistor R9, a fixed capacitor C5, a fixed capacitor C6, a fixed capacitor C7 and a fixed capacitor C8; The OUT pin of the second operational amplifier is connected to one end of the fixed resistor R7 and one end of the fixed resistor R9, the other end of the fixed resistor R7 is connected to one end of the fixed resistor R5, one end of the fixed capacitor C6 and one end of the fixed capacitor C5, the other end of the fixed resistor R9 is connected to one end of the fixed resistor R8, one end of the fixed resistor R8 is also connected to the reverse input end of the second operational amplifier, the other end of the fixed resistor R5 is connected to the ultrasonic receiving signal amplification module, the other end of the fixed capacitor C6 is connected to one end of the fixed resistor R6, the other end of the fixed capacitor C6 is also connected to the same direction input end of the second operational amplifier, the other end of the fixed resistor R6 and the other end of the fixed capacitor C5 are both connected to the other end of the fixed resistor R8; the positive and negative poles of the power supply of the second operational amplifier are connected to the power supply, one end of the fixed capacitor C8 and one end of the fixed capacitor C7 are respectively connected to the positive and negative poles of the power supply of the second operational amplifier, and the other end of the fixed capacitor C8 and the other end of the fixed capacitor C7 are both grounded.
5. The phase reversal point detection circuit of the ultrasonic receiving waveform envelope according to claim 1, characterized in that: The detection module includes a fixed resistor R10 and a fixed capacitor C9 connected in parallel. After being connected in parallel, the fixed resistor R10 and the fixed capacitor C9 are connected in series with a detection diode. One end of the fixed resistor R10 and the fixed capacitor C9 connected in parallel is grounded, and the other end of the fixed resistor R10 and the fixed capacitor C9 connected in parallel is connected to the cathode of the detection diode. The other end of the fixed resistor R10 and the fixed capacitor C9 connected in parallel is also connected to the low-pass filtering module, and the anode of the detection diode is connected to the band-pass filtering amplification module.
6. The phase reversal point detection circuit of the ultrasonic receiving waveform envelope according to claim 5, characterized in that: The model of the detection diode used is IN60.
7. The phase reversal point detection circuit of the ultrasonic receiving waveform envelope according to claim 1, characterized in that: The low-pass filter module includes a third operational amplifier, a fixed resistor R11, a fixed resistor R12, a fixed capacitor C10, a fixed capacitor C11, a fixed capacitor C12 and a fixed capacitor C13; The same-direction input terminal of the third operational amplifier is connected to one end of the fixed resistor R12, the other end of the fixed resistor R12 is connected to one end of the fixed resistor R11, and the other end of the fixed resistor R11 is connected to the detection module; the same-direction input terminal of the third operational amplifier is also connected to one end of the fixed capacitor C10, and the other end of the fixed capacitor C10 is grounded; the reverse input terminal of the third operational amplifier is connected to the OUT pin of the third operational amplifier, the reverse input terminal of the third operational amplifier is also connected to one end of the fixed capacitor C11, and the other end of the fixed capacitor C11 is connected to the other end of the fixed resistor R12; the positive and negative poles of the power supply of the third operational amplifier are connected to the power supply, one end of the fixed capacitor C12 and one end of the fixed capacitor C13 are respectively connected to the positive and negative poles of the power supply of the third operational amplifier, and the other end of the fixed capacitor C12 and the other end of the fixed capacitor C13 are both grounded.
8. The phase reversal point detection circuit of the ultrasonic receiving waveform envelope according to claim 1, characterized in that: The differential module includes a fourth operational amplifier, a fixed resistor R13, a fixed resistor R14, a fixed resistor R15, a fixed capacitor C14, a fixed capacitor C15 and a fixed capacitor C16; The reverse input terminal of the fourth operational amplifier is connected to one end of the fixed resistor R14, the other end of the fixed resistor R14 is connected to the OUT pin of the fourth operational amplifier, the reverse input terminal of the fourth operational amplifier is also connected to one end of the fixed capacitor C14, one end of the fixed capacitor C14 is connected to one end of the fixed resistor R13, and the other end of the fixed resistor R13 is connected to the low-pass filter module; the same-direction input terminal of the fourth operational amplifier is connected to one end of the fixed resistor R15, and the other end of the fixed resistor R15 is grounded; the positive and negative poles of the power supply of the fourth operational amplifier are connected to the power supply, one end of the fixed capacitor C15 and one end of the fixed capacitor C16 are respectively connected to the positive and negative poles of the power supply of the fourth operational amplifier, and the other end of the fixed capacitor C15 and the other end of the fixed capacitor C16 are both grounded.
9. The phase reversal point detection circuit of the ultrasonic receiving waveform envelope according to claim 1, characterized in that: The zero-crossing detection module includes a fifth operational amplifier, a diode, a fixed resistor R16, a fixed resistor R17, a fixed resistor R18, a fixed resistor R19, a fixed resistor 20, a fixed resistor R21, a fixed resistor R22 and a fixed capacitor C17; The same-direction input terminal of the fifth operational amplifier is connected to one end of the fixed resistor R21, and the other end of the fixed resistor R21 is grounded; the reverse input terminal of the fifth operational amplifier is connected to one end of the fixed resistor R17, and the other end of the fixed resistor R17 is connected to one end of the fixed resistor R16, and the other end of the fixed resistor R17 is also connected to the cathode of the diode, and the anode of the diode is grounded, and the other end of the fixed resistor R16 is connected to the differential module; the 1OUT pin of the fifth operational amplifier is connected to one end of the fixed resistor R20, and the fixed resistor R2 The other end of 0 is connected to one end of a fixed resistor R19, and the other end of the fixed resistor R19 is connected to a power supply; the other end of the fixed resistor R19 is also connected to one end of a fixed resistor R18, and the other end of the fixed resistor R18 is connected to one end of a fixed resistor R17; the 1OUT pin of the fifth operational amplifier is also connected to one end of a fixed resistor R22, and the other end of the fixed resistor R22 is connected to the other end of the fixed resistor R19; the VCC pin of the fifth operational amplifier is connected to one end of a fixed capacitor C17, and the other end of the fixed capacitor C17 is grounded.
10. The phase reversal point detection circuit of the ultrasonic receiving waveform envelope according to claim 9, characterized in that: The model of the fifth operational amplifier is LM393, and the model of the diode is IN914.