A Stethoscope with Wavelet Separation of Cardiac and Respiratory Sounds for Real Time Telemedicine Implemented on Field-Programmable Gate Array

Auscultation is one of the most utilized physical examination procedures for listening to lung, heart and intestinal sounds during routine consults and emergencies. Heart and lung sounds overlap in the thorax. An algorithm was used to separate them based on the discrete wavelet transform with multi-resolution analysis, which decomposes the signal into approximations and details. The algorithm was implemented in software and in hardware to achieve realtime signal separation. The heart signal was found in detail eight and the lung signal in approximation six. The hardware was used to separate the signals with a delay of 256 ms. Sending wavelet decomposition data -instead of the separated full signal-allows telemedicine applications to function in real time over low-bandwidth communication channels.