A developed design to enlarge the spectrum for analog electronic stethoscope

Bioacoustic signal from human organ in range of infrasound to ultrasound was not investigated. The signal might provide significant for clinical diagnostics in the future. In this report, a front-end analog system included large spectrum prepolarized condenser microphone sensor and analog amplifier with 4th order active filters, was designed. The measurement spectrums are ranged from 5 Hz to 40 kHz. The amplifier gain can be adjusted in range of 40 dB to 100 dB. To record the measured data for analysis, the analog signal were converted to numerical data and transfer to computer through a commercial ADC module. To evaluate the system, human heart sound from a volunteer were measured and analyzed with Fourier Transform to obtain signal to noise ratio (SNR) of 50 dB. With the enlargement of the signal spectrum and high SNR as well as high amplification, this pilot device is believed to be the new utility for clinical diagnosis. © 2019 Eastern Macedonia and Thrace Institute of Technology.