CN2363659Y - Portable high fidelity electronic stethoscope - Google Patents

Abstract

The utility model relates to a portable hi-fi electronic stethoscope, which comprises a probe head (1) that is the stethoscope head of the stethoscope, the inner part of the probe head (1) is provided with a piezoelectric ceramic sheet BC, a low-pass filter (2) is a three stage LC filter, a preamplification circuit (3) adopts an integrated circuit block IC1 which has the model number of BA328, an LF power amplifier (4) adopts integrated circuit blocks (IC2A, IC2B) which has the model number of TDA2822, and the earphone part is a pair of stereo headphones or a recorder (5). The utility model has the advantages of strong anti-interference capability, high fidelity, high sensitivity, large volume, small size and convenient carryover.

Description

Portable high-fidelity electronic stethoscope

Portable high-fidelity electronic stethoscope relates to stethoscope, relates in particular to the electronic stethoscope that adopts electronic technology.

Prior art Chinese patent publication number CN1118244A, name is called stethoscope, and shortcoming is, and not to the high-frequency cacophony filtering, thereby noise is big, and sensitivity is low.The air-conduction type stethoscope in use is subject to disturb and produces noise, and sensitivity is low.

The purpose of this utility model is to overcome above-mentioned shortcoming, and a kind of highly sensitive, strong interference immunity, portable high-fidelity electronic stethoscope that volume is little are provided.

Technical characterstic of the present utility model is as follows:

A kind of portable high-fidelity electronic stethoscope is characterized in that: probe (1) is stethoscopic can, and piezoelectric ceramic piece BC is arranged in it, piezoelectric ceramic piece BC connects low pass filter (2), connect pre-amplification circuit (3) again, connect LF power amplifier (4) again, again lug machine or recorder (5).

Low pass filter (2) comprises three grades of LC wave filter.

It is chip IC1 and the peripheral cell thereof of BA328 that pre-amplification circuit (3) adopts model.

It is part IC2A and the IC2B and the peripheral cell thereof of the chip of TDA2822 that LF power amplifier (4) adopts model.Operation principle:

The mechanical vibration of sound wave are converted into the voltage signal that changes with sound wave through piezoelectric ceramic piece BC, send into by R1 C2, R2, C3, R3, three grades of low pass wave filters that C4 forms are unnecessary radio-frequency component and by auscultation probe and the fricative ear-piercing noise-filtering of thoracic wall.Again with filtering the audio signal of noise and radio-frequency component amplify through C5 input preamplifier IC 1, the IC1 model is BA328, its open-loop gain reaches 70dB, total harmonic distortion is lower than 0.1%, is the high preposition amplification circuit of fidelity.

The audio signal that IC1 has amplified is regulated after C10, C11, the IC2A, the in-phase end of IC2B of power amplification circuit TDA2822 amplify frequently to send into double-tone respectively through W1, input to earphone BL1, BL2 through C14, C18 again and be reduced to sound, just can carry out auscultation hear sounds and pulmonary respiration sound.

Advantage:

1, more old-fashioned stethoscope volume increase is more, helps improving the diagnosis rate to patient.

2, old-fashioned stethoscope is subject to disturb to produce noise, and this instrument adopts three grades of low pass wave filters, effectively filtering noise, improved the capacity of resisting disturbance of instrument.

3, audio signal is amplified Hi-Fi preposition amplification circuit of employing and low frequency power amplification circuit, and the fidelity height can truly reflect hear sounds, the variation of pulmonary respiration sound in earphone.

4, because pre-amplification circuit has higher gain, so the sensitivity of this instrument is very high.

5, earphone adopts hood type, has avoided ear plug of stethoscope to wear for a long time the ear discomfort that produces.Owing to be hood type, can also alleviate ambient noise to stethoscopic influence.

6, mixing recorder can also record the heart, lungs sound get off, and uses for the consultation of doctors.

Description of drawings:

Fig. 1: portable high-fidelity electronic stethoscope circuit block diagram of the present utility model.

Fig. 2: portable high-fidelity electronic stethoscope circuit theory diagrams of the present utility model.

Describe embodiment of the present utility model in detail below in conjunction with accompanying drawing.

See Fig. 1, portable high-fidelity electronic stethoscope circuit block diagram of the present utility model.Probe (1) is stethoscopic can, and piezoelectric ceramic piece BC is arranged in it, and piezoelectric ceramic piece BC connects low pass filter (2), connects pre-amplification circuit (3) again, connects LF power amplifier (4) again, again lug machine or recorder (5).

See Fig. 2, low pass filter (2) comprising:

Piezoelectric ceramic piece BC meets R1, C1, another termination of R1 R2, C2, and another termination of R2 R3, C3, another termination of R3 C4, R4, C5, the C5 negative terminal connects 2 feet of IC1; The other end ground connection of the piezoelectric ceramic piece BC other end, C1, C2, C3, C4 and R4.

It is chip IC1 and the peripheral cell thereof of BA328 that pre-amplification circuit (3) adopts model.Comprise: 1 foot meets C6, another termination 8 feet of C6, and 3 feet connect R5, C8, C9 anode, 4 foot rooms, 5 foot ground connection, 6 foot rooms, 7 feet connect the C7 anode, and 8 feet meet the C6 other end, R5, C8, and 9 feet connect C20, K switch 1, C7 ground connection.Another termination power positive end of K1.

It is the part IC2A and the IC2B of the chip of TDA2822 that LF power amplifier (4) adopts model, and peripheral cell.

The IC2A connected mode: the C9 negative terminal connects fixed end of potentiometer W1, another fixed end ground connection of W1, and the moved end of W1 connects C10, C11 negative terminal; Amplifier IC2A end of oppisite phase (-) 8 feet connect the C13 anode, and IC2A in-phase end (+) 7 feet connect C12, R6 and C10 anode, and IC2A outfan 1 foot connects the C14 anode; The C14 negative terminal meets C15, earphone BL1, another termination of C15 R7; C12, R6, C13, R7, BL1 other end ground connection.2 feet of IC2A meet C20 anode and K1.

The IC2B connected mode: IC2B in-phase end (+) 6 feet meet C11 anode, C16, R8; End of oppisite phase (-) 5 feet of IC2B connect the C17 anode; C16, R8, C17 other end ground connection; Outfan 3 feet of IC2B connect the anode of C18; The C18 negative terminal meets C19 and earphone BL2; Another termination R9 of C19, the other end of R9, BL2 other end ground connection, the 4 foot ground connection of IC2B.

Among Fig. 2, R1 to R9 is a resistance, and C1 to C20 is an electric capacity, and W1 is a potentiometer, and K1 is a switch, and BL1, BL2 are earphone, and BC is a piezoelectric ceramic piece, power supply usefulness+3V power supply.

Claims (4)

1, a kind of portable high-fidelity electronic stethoscope, comprise: probe, amplifying circuit, earphone, it is characterized in that: probe (1) is stethoscopic can, piezoelectric ceramic piece BC is arranged in it, piezoelectric ceramic piece BC connects low pass filter (2), connect pre-amplification circuit (3) again, connect LF power amplifier (4) again, again lug machine or recorder (5).

2, portable high-fidelity electronic stethoscope according to claim 1, it is characterized in that: low pass filter (2) comprises three grades of LC wave filter.

3, portable high-fidelity electronic stethoscope according to claim 2 is characterized in that: it is chip IC1 and the peripheral cell thereof of BA328 that pre-amplification circuit (3) adopts model.

4, portable high-fidelity electronic stethoscope according to claim 3 is characterized in that: it is part IC2A and the IC2B and the peripheral cell thereof of the chip of TDA2822 that LF power amplifier (4) adopts model.