This paper designs a heart sound processing analog circuit, in which the amplification circuit, the filter circuit and the lifting of electrical level circuit are involved. It also gives a safety design problem analysis using an electret capacitor microphone to pick-up the heart sound signals. It is proved that the circuit is reliable and effective.

In this paper is described a comprehensive system, which can acquire heart sounds and electrocardiogram (ECG) in parallel, synchronize the display; and play of heart sound and make auscultation and check phonocardiogram to tie in. The hardware system with C8051F340 as the core acquires the heart sound and ECG synchronously, and then sends them to indicators, respectively. Heart sounds are displayed and played simultaneously by controlling the moment of writing to indicator and sound output device. In clinical testing, heart sounds can be successfully located with ECG and real-time played.
Electrocardiography ; instrumentation ; methods ; Humans ; Monitoring, Physiologic ; Phonocardiography ; instrumentation ; methods ; Signal Processing, Computer-Assisted