PC based monitoring of human heart sounds

The paper presents an instrumentation system developed for monitoring of human heart sounds. A condenser microphone senses the heart sounds converting them into an equivalent electrical signal. The signal is suitably amplified and filtered in desired frequency band. This signal is converted to equivalent digital signal by an A/D conversion circuitry developed for the purpose. This digital signal is then fed to PC through the printer port (Syntronix). With the help of the supporting software, the signal for a specific duration is accessed and stored in the PC memory. This is further processed for its frequency contents. The system is simple and compact and does not require any external A/D card for the PC. It can be very useful for monitoring human heart sounds and interpreting the sounds on the basis of their time domain and frequency domain representation to diagnose heart disorders.