Design and implementation of a remote embedded DSP stethoscope with a method for judging heart murmur

Abstract

In this paper we design an embedded DSP (Digital Signal Processing) stethoscope with the functions of network transmission and the judging of heart murmur by using a diagram which includes both the time domain and the frequency domain. Judging the pathological and functional heart murmur aspects helps doctors diagnose a heart murmur. A patient can also easily learn the procedure and then record his heart sounds at any desired moment. The design and the implementation of the embedded DSP stethoscope consist of two steps. For the first step we change a traditional stethoscope into a digital stethoscope by inserting an electric capacity microphone into its head. The heart signals, therefore, are picked up, amplified by the amplifier and then transmitted to the embedded DSP board for signal processing which reduces the noise and obtains a clear heart sound signal. For the second step we use the embedded DSP board to obtain the frequency band of the heart sound signals through a digital filter. Then we use a fast independent component analysis algorithm (FastICA) to detect and divide the heart sounds and the lung sounds, and then we can discern from the oscillogram whether any heart murmur is systolic or diastolic. In addition, the heart sounds are transferred to the frequency domain through Fast Fourier Transform (FFT) to be compared with a normal heart sound in order to judge the heart murmur.