CN219554930U - Body sound detection circuit for multipoint measurement - Google Patents

Body sound detection circuit for multipoint measurement Download PDF

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Publication number
CN219554930U
CN219554930U CN202320622357.8U CN202320622357U CN219554930U CN 219554930 U CN219554930 U CN 219554930U CN 202320622357 U CN202320622357 U CN 202320622357U CN 219554930 U CN219554930 U CN 219554930U
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resistor
circuit
operational amplifier
input end
output
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莫鸿强
何正达
田翔
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South China University of Technology SCUT
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South China University of Technology SCUT
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
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    • Y02A90/30—Assessment of water resources

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Abstract

The utility model provides a body sound detection circuit for multipoint measurement, which comprises a detection end circuit and an output circuit; the detection end circuit comprises a piezoelectric film sensor, a voltage bias circuit, an amplifying and filtering circuit and a single-ended signal-to-differential signal circuit; the single-ended signal-to-differential signal circuit comprises a voltage follower circuit and an inverse bias circuit; the piezoelectric film sensor is connected with the voltage follower circuit through the amplifying and filtering circuit; the voltage follower circuit is connected with the reverse bias circuit; the piezoelectric film sensor is also connected with the reverse bias circuit through the voltage bias circuit; the output circuit is a differential signal-to-single-ended signal circuit for converting a differential signal into a single-ended signal. The body sound detection circuit transmits the measured body sound auscultation signals in the form of differential signals, so that the common mode interference resistance of the whole circuit can be improved, and a guarantee is provided for simultaneous auscultation of multiple parts.

Description

Body sound detection circuit for multipoint measurement
Technical Field
The utility model relates to the technical field of medical appliances, in particular to a body sound detection circuit for multipoint measurement.
Background
The body sound auscultation can assist in diagnosing heart and lung system diseases and digestive system diseases, and evaluating the stenosis degree of arteriovenous fistula. In the auscultation process, a doctor moves the stethoscope and places the stethoscope at a specific part, such as the throat, the suprasternal fossa, the tip of the lung and the like, for auscultation and diagnosis of the illness state. When auscultation is performed on body sounds of different parts, the auscultators need to be adjusted to the corresponding parts according to a certain sequence, and the auscultation method is not beneficial to detecting multi-point body sound signals in real time.
In order to realize real-time monitoring of body sounds at multiple points, such as simultaneous auscultation at the apex of heart, the fossa on sternum and the apex of left and right lungs or multiple points of arteriovenous fistula, it is conceivable to collect body sound signals simultaneously by using multiple body sound sensors and connect each body sound sensor to a processor; the processor performs digital filtering and other processing on the signals and uploads the processing result to the upper computer.
If the hardware circuit is realized in the mode, the fact that interference signals such as power frequency noise and the like possibly enter an AD conversion circuit through a connecting wire between the body sound sensor and the processor is considered to form common-mode interference; therefore, the body sound sensors cannot be connected with the processor, and a circuit capable of solving common mode interference needs to be added to the transmission path of the body sound sensors and the processor.
Disclosure of Invention
The utility model aims to overcome the defects and shortcomings in the prior art and provides a body sound detection circuit for multi-point measurement; the body sound detection circuit transmits the measured body sound auscultation signals in the form of differential signals, so that the common mode interference resistance of the whole circuit can be improved, and a guarantee is provided for simultaneous auscultation of multiple parts.
In order to achieve the above purpose, the utility model is realized by the following technical scheme: a body sound detection circuit for multipoint measurement comprises a detection end circuit and an output circuit; the detection end circuit comprises a piezoelectric film sensor for converting a body sound auscultation signal into a voltage signal, a voltage bias circuit for performing bias treatment on the voltage signal, an amplifying and filtering circuit for amplifying and bandpass filtering the voltage signal, and a single-ended signal-to-differential signal circuit for converting the voltage signal into a differential signal;
the single-ended signal-to-differential signal circuit comprises a voltage follower circuit and an inverse bias circuit; the piezoelectric film sensor is connected with the voltage follower circuit through the amplifying and filtering circuit; the voltage follower circuit is connected with the reverse bias circuit; the piezoelectric film sensor is also connected with an inverse bias circuit through a voltage bias circuit;
the output circuit is a circuit for converting a differential signal into a single-ended signal.
Preferably, the voltage bias circuit includes a capacitor C1, a capacitor C2, a diode D1, a diode D2, a resistor R1, a resistor R2, and a resistor R3; the diode D1 and the diode D2 are connected in series and then connected between the power supply and the ground; the diode D2 and the capacitor C2 are respectively connected with the piezoelectric film sensor in parallel; the capacitor C1 is connected with the diode D1 in parallel; the resistor R2 and the resistor R3 are connected in series and then connected between a power supply and the ground; the connection part of the resistor R2 and the resistor R3 is connected with the connection part of the diode D1 and the diode D2 through the resistor R1;
the amplifying and filtering circuit comprises an operational amplifier U1A, a capacitor C3, a capacitor C4, a resistor R5 and a resistor R6; the positive input end of the operational amplifier U1A is connected with the junction of the diode D1 and the diode D2; the negative input end of the operational amplifier U1A is grounded through a resistor R4 and a capacitor C3 which are connected in series; the negative input end of the operational amplifier U1A is also connected with the output end of the operational amplifier U1A through a resistor R5 and a capacitor C4 which are connected in parallel; the output end of the operational amplifier U1A is grounded through a resistor R6;
the voltage follower circuit comprises an operational amplifier U1B and a resistor R7; the reverse bias circuit comprises an operational amplifier U2A, a capacitor C5, a resistor R8 and a resistor R9;
the output end of the operational amplifier U1A is connected with the positive input end of the operational amplifier U1B through a resistor R7; the negative input end of the operational amplifier U1B is connected with the output end of the operational amplifier U1B; the output end of the operational amplifier U1B is connected with the negative input end of the operational amplifier U2A through a resistor R8; the junction of the resistor R2 and the resistor R3 is connected with the positive input end of the operational amplifier U2A; the positive input end of the operational amplifier U2A is grounded through a capacitor C5; the negative input end of the operational amplifier U2A is connected with the output end of the operational amplifier U2A through a resistor R9; the output end of the operational amplifier U1B is used as an output end A+ of the detection end circuit; the output end of the operational amplifier U2A is used as the output end A-of the detection end circuit.
Preferably, the resistances of the resistor R8 and the resistor R9 are equal.
Preferably, the differential signal to single-ended signal circuit includes an operational amplifier U2B, an operational amplifier U3A, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a capacitor C6, and a capacitor C7;
the resistor R17 and the resistor R18 are connected between a power supply and ground; the junction of the resistor R17 and the resistor R18 is connected with the positive input end of the operational amplifier U2B through a resistor R11; the positive input end of the operational amplifier U2B is grounded through a capacitor C6; the input end A' + of the output circuit is connected with the negative input end of the operational amplifier U2B through a resistor R10, and the negative input end of the operational amplifier U2B is connected with the output end of the operational amplifier U2B through a resistor R12;
the junction of the resistor R17 and the resistor R18 is also connected with the positive input end of the operational amplifier U3A through a resistor R15; the positive input end of the operational amplifier U3A is grounded through a capacitor C7; the input end A' -of the output circuit is connected with the negative input end of the operational amplifier U3A through a resistor R14; the output end of the operational amplifier U2B is connected with the negative input end of the operational amplifier U3A through a resistor R13; the negative input end of the operational amplifier U3A is connected with the output end of the operational amplifier U3A through a resistor R16; the output of the operational amplifier U3A serves as the output of the output circuit.
Preferably, the resistances of the resistor R17 and the resistor R18 are equal.
Preferably, the output end A+ of the detection end circuit is in signal connection with the input end A' + of the output circuit; the output end A-of the detection end circuit is connected with the input end A' -of the output circuit in a signal mode.
Preferably, the output end A+ of the detection end circuit and the input end A '+ of the output circuit and the output end A-of the detection end circuit and the input end A' -of the output circuit are in signal connection through long wires.
Compared with the prior art, the utility model has the following advantages and beneficial effects:
1. according to the body sound detection circuit, the detection end circuit amplifies and filters the detected body sound auscultation signals, and transmits the amplified and filtered body sound auscultation signals to the output circuit beyond a certain distance in the form of differential signals, so that the common mode interference resistance of the whole circuit can be improved, and a guarantee is provided for simultaneous auscultation of multiple parts; the output circuit converts the differential signal into a single-ended signal and outputs the single-ended signal for processing by a subsequent singlechip.
2. The body sound detection circuit can amplify the body sound auscultation signal without distortion; the roll-off of-40 dB/dec is arranged outside the effective frequency band of the body sound auscultation signal, so that low-frequency noise caused by diaphragm vibration and other reasons and high-frequency noise caused by other reasons can be effectively restrained.
Drawings
Fig. 1 is a block diagram of a body sound detection circuit for multipoint measurement according to the present utility model;
fig. 2 is a schematic structural diagram of a detection end circuit in a body sound detection circuit for multipoint measurement according to the present utility model;
FIG. 3 is a schematic diagram of the structure of the output circuit in the body sound detection circuit for multi-point measurement according to the present utility model;
fig. 4 is a logarithmic amplitude-frequency characteristic curve of the body-sound detection circuit for multipoint measurement according to the present utility model when the amplification filter circuit parameters take preferred values.
Detailed Description
The utility model is described in further detail below with reference to the drawings and the detailed description.
Examples
As shown in fig. 1 to 3, a body sound detection circuit for multipoint measurement according to the present embodiment includes a detection end circuit and an output circuit.
The detection end circuit comprises a piezoelectric film sensor for converting a body sound auscultation signal into a voltage signal, a voltage bias circuit for performing bias processing on the voltage signal, an amplifying and filtering circuit for amplifying and bandpass filtering the voltage signal, and a single-ended signal-to-differential signal circuit for converting the voltage signal into a differential signal.
The single-ended signal-to-differential signal circuit comprises a voltage follower circuit and an inverse bias circuit; the piezoelectric film sensor is connected with the voltage follower circuit through the amplifying and filtering circuit; the voltage follower circuit is connected with the reverse bias circuit; the piezoelectric film sensor is also connected with the reverse bias circuit through the voltage bias circuit.
Specifically, the voltage bias circuit includes a capacitor C1, a capacitor C2, a diode D1, a diode D2, a resistor R1, a resistor R2, and a resistor R3; the diode D1 and the diode D2 are connected in series and then connected between the power supply and the ground; the diode D2 and the capacitor C2 are respectively connected with the piezoelectric film sensor in parallel; the capacitor C1 is connected with the diode D1 in parallel; the resistor R2 and the resistor R3 are connected in series and then connected between a power supply and the ground; the junction of the resistor R2 and the resistor R3 is connected with the junction of the diode D1 and the diode D2 through the resistor R1.
In the voltage bias circuit, the capacitors C1 and C2 are used for suppressing high-frequency noise, and the diodes D1 and D2 are used for suppressing electrostatic interference; the resistors R1-R3 are used for generating bias voltage, and when the selected parameter is a preferred value, the resistance values of R2 and R3 are equal, and the magnitude of the bias voltage is 1/2VCC.
The amplifying and filtering circuit comprises an operational amplifier U1A, a capacitor C3, a capacitor C4, a resistor R5 and a resistor R6; the positive input end of the operational amplifier U1A is connected with the junction of the diode D1 and the diode D2; the negative input end of the operational amplifier U1A is grounded through a resistor R4 and a capacitor C3 which are connected in series; the negative input end of the operational amplifier U1A is also connected with the output end of the operational amplifier U1A through a resistor R5 and a capacitor C4 which are connected in parallel; the output of the operational amplifier U1A is grounded through a resistor R6.
The amplifying and filtering circuit realizes amplifying and band-pass filtering, and the cut-off frequency of the band-pass filtering depends on the values of C3, C4, R4 and R5.
The voltage follower circuit comprises an operational amplifier U1B and a resistor R7; the reverse bias circuit comprises an operational amplifier U2A, a capacitor C5, a resistor R8 and a resistor R9; the resistances of the resistor R8 and the resistor R9 are equal.
The output end of the operational amplifier U1A is connected with the positive input end of the operational amplifier U1B through a resistor R7; the negative input end of the operational amplifier U1B is connected with the output end of the operational amplifier U1B; the output end of the operational amplifier U1B is connected with the negative input end of the operational amplifier U2A through a resistor R8; the junction of the resistor R2 and the resistor R3 is connected with the positive input end of the operational amplifier U2A; the positive input end of the operational amplifier U2A is grounded through a capacitor C5; the negative input end of the operational amplifier U2A is connected with the output end of the operational amplifier U2A through a resistor R9; the output end of the operational amplifier U1B is used as an output end A+ of the detection end circuit; the output end of the operational amplifier U2A is used as the output end A-of the detection end circuit.
The output circuit is a differential signal-to-single-ended signal circuit for converting a differential signal into a single-ended signal.
Specifically, an output end A+ of the detection end circuit is connected with an input end A' + signal of the output circuit; the output end A-of the detection end circuit is connected with the input end A' -of the output circuit through signals; preferably by long wires. The differential signal to single-ended signal circuit comprises an operational amplifier U2B, an operational amplifier U3A, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a capacitor C6 and a capacitor C7.
The resistor R17 and the resistor R18 are connected between the power supply and the ground; the junction of the resistor R17 and the resistor R18 is connected with the positive input end of the operational amplifier U2B through a resistor R11; the positive input end of the operational amplifier U2B is grounded through a capacitor C6; the input terminal A' + of the output circuit is connected with the negative input terminal of the operational amplifier U2B through a resistor R10, and the negative input terminal of the operational amplifier U2B is connected with the output terminal of the operational amplifier U2B through a resistor R12.
The junction of resistor R17 and resistor R18 is also connected to the positive input of operational amplifier U3A through resistor R15. The bias voltage of the differential signal-to-single-ended signal circuit is generated by resistors R17 and R18; the resistance values of the resistor R17 and the resistor R18 are equal, and the bias voltage is 1/2VCC. The positive input end of the operational amplifier U3A is grounded through a capacitor C7; the input end A' -of the output circuit is connected with the negative input end of the operational amplifier U3A through a resistor R14; the output end of the operational amplifier U2B is connected with the negative input end of the operational amplifier U3A through a resistor R13; the negative input end of the operational amplifier U3A is connected with the output end of the operational amplifier U3A through a resistor R16; the output of the operational amplifier U3A serves as the output of the output circuit.
The working principle of the detection end circuit is as follows: the voltage at the output end of the piezoelectric film sensor is V in (s)＝V ref +ΔV in (s) wherein V ref For bias voltage DeltaV in (s) is the voltage increment due to body sounds. V (V) in (s) amplified and filtered, converted to differential signals, and output from the A+ and A-ports. V (V) in (s) and A+ port voltage V A+ (s), A-Port Voltage V A- (s) bias voltage V ref The relation between the two is:
V A- (s)＝2V ref -V A+ (s)
the working principle of the output circuit is as follows: the differential signals input by the A '+ and A' -ports are converted into single-ended signals to be output from the output port. The A' + port voltage is recorded as V A+ (s), A' -port voltage of V A- (s), output port output voltage is V output (s) the relationship of the three is:
V output (s)＝V A+ (s)-V A- (s)
recording deviceThen
V output (s)＝2[1+G(s)]ΔV in (s)+G(s)V ref
So that the body sound detection circuit outputs V output (s) vs. the body voltage signal DeltaV in The transfer function of(s) is
For common mode interference in body-sound multi-point auscultation, preferred values of the parameters of the components in this embodiment are shown in table 1.
TABLE 1 preferred values for the various component parameters
The logarithmic frequency characteristic curve when the amplification filter circuit parameter takes the preferred value is shown in fig. 4. According to the effective frequency band selection circuit parameters of the body sound auscultation signals, the body sound auscultation signals can be amplified without distortion; the roll-off of-40 dB/dec is arranged outside the effective frequency band of the body sound auscultation signal, so that low-frequency noise caused by diaphragm vibration and other reasons and high-frequency noise caused by other reasons can be effectively restrained.
The above examples are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present utility model should be made in the equivalent manner, and the embodiments are included in the protection scope of the present utility model.

Claims (7)

1. A body sound detection circuit for multipoint measurement, characterized in that: the device comprises a detection end circuit and an output circuit; the detection end circuit comprises a piezoelectric film sensor for converting a body sound auscultation signal into a voltage signal, a voltage bias circuit for performing bias treatment on the voltage signal, an amplifying and filtering circuit for amplifying and bandpass filtering the voltage signal, and a single-ended signal-to-differential signal circuit for converting the voltage signal into a differential signal;
the single-ended signal-to-differential signal circuit comprises a voltage follower circuit and an inverse bias circuit; the piezoelectric film sensor is connected with the voltage follower circuit through the amplifying and filtering circuit; the voltage follower circuit is connected with the reverse bias circuit; the piezoelectric film sensor is also connected with an inverse bias circuit through a voltage bias circuit;
the output circuit is a circuit for converting a differential signal into a single-ended signal.
2. The body sound detection circuit for multipoint measurement according to claim 1, wherein: the voltage bias circuit comprises a capacitor C1, a capacitor C2, a diode D1, a diode D2, a resistor R1, a resistor R2 and a resistor R3; the diode D1 and the diode D2 are connected in series and then connected between the power supply and the ground; the diode D2 and the capacitor C2 are respectively connected with the piezoelectric film sensor in parallel; the capacitor C1 is connected with the diode D1 in parallel; the resistor R2 and the resistor R3 are connected in series and then connected between a power supply and the ground; the connection part of the resistor R2 and the resistor R3 is connected with the connection part of the diode D1 and the diode D2 through the resistor R1;
the amplifying and filtering circuit comprises an operational amplifier U1A, a capacitor C3, a capacitor C4, a resistor R5 and a resistor R6; the positive input end of the operational amplifier U1A is connected with the junction of the diode D1 and the diode D2; the negative input end of the operational amplifier U1A is grounded through a resistor R4 and a capacitor C3 which are connected in series; the negative input end of the operational amplifier U1A is also connected with the output end of the operational amplifier U1A through a resistor R5 and a capacitor C4 which are connected in parallel; the output end of the operational amplifier U1A is grounded through a resistor R6;
the voltage follower circuit comprises an operational amplifier U1B and a resistor R7; the reverse bias circuit comprises an operational amplifier U2A, a capacitor C5, a resistor R8 and a resistor R9;
the output end of the operational amplifier U1A is connected with the positive input end of the operational amplifier U1B through a resistor R7; the negative input end of the operational amplifier U1B is connected with the output end of the operational amplifier U1B; the output end of the operational amplifier U1B is connected with the negative input end of the operational amplifier U2A through a resistor R8; the junction of the resistor R2 and the resistor R3 is connected with the positive input end of the operational amplifier U2A; the positive input end of the operational amplifier U2A is grounded through a capacitor C5; the negative input end of the operational amplifier U2A is connected with the output end of the operational amplifier U2A through a resistor R9; the output end of the operational amplifier U1B is used as an output end A+ of the detection end circuit; the output end of the operational amplifier U2A is used as the output end A-of the detection end circuit.
3. The body sound detection circuit for multipoint measurement according to claim 2, wherein: the resistance values of the resistor R8 and the resistor R9 are equal.
4. The body sound detection circuit for multipoint measurement according to claim 2, wherein: the differential signal to single-ended signal conversion circuit comprises an operational amplifier U2B, an operational amplifier U3A, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a capacitor C6 and a capacitor C7;
the resistor R17 and the resistor R18 are connected between a power supply and ground; the junction of the resistor R17 and the resistor R18 is connected with the positive input end of the operational amplifier U2B through a resistor R11; the positive input end of the operational amplifier U2B is grounded through a capacitor C6; the input end A' + of the output circuit is connected with the negative input end of the operational amplifier U2B through a resistor R10, and the negative input end of the operational amplifier U2B is connected with the output end of the operational amplifier U2B through a resistor R12;
the junction of the resistor R17 and the resistor R18 is also connected with the positive input end of the operational amplifier U3A through a resistor R15; the positive input end of the operational amplifier U3A is grounded through a capacitor C7; the input end A' -of the output circuit is connected with the negative input end of the operational amplifier U3A through a resistor R14; the output end of the operational amplifier U2B is connected with the negative input end of the operational amplifier U3A through a resistor R13; the negative input end of the operational amplifier U3A is connected with the output end of the operational amplifier U3A through a resistor R16; the output of the operational amplifier U3A serves as the output of the output circuit.
5. The body sound detection circuit for multipoint measurement according to claim 4, wherein: the resistance values of the resistor R17 and the resistor R18 are equal.
6. The body sound detection circuit for multipoint measurement according to claim 4, wherein: the output end A+ of the detection end circuit is connected with the input end A' + of the output circuit through signals; the output end A-of the detection end circuit is connected with the input end A' -of the output circuit in a signal mode.
7. The body sound detection circuit for multipoint measurement according to claim 6, wherein: the output end A+ of the detection end circuit is connected with the input end A '+ of the output circuit, and the output end A-of the detection end circuit is connected with the input end A' -of the output circuit through long lead signals.
CN202320622357.8U 2023-03-27 2023-03-27 Body sound detection circuit for multipoint measurement Active CN219554930U (en)

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Application Number Priority Date Filing Date Title
CN202320622357.8U CN219554930U (en) 2023-03-27 2023-03-27 Body sound detection circuit for multipoint measurement

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202320622357.8U CN219554930U (en) 2023-03-27 2023-03-27 Body sound detection circuit for multipoint measurement

Publications (1)

Publication Number Publication Date
CN219554930U true CN219554930U (en) 2023-08-18

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Application Number Title Priority Date Filing Date
CN202320622357.8U Active CN219554930U (en) 2023-03-27 2023-03-27 Body sound detection circuit for multipoint measurement

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