A system of generating a spectral phonocardiogram which summarizes time-dependent changes in the heart sounds throughout the heart cycle. The system is based on the projection of spectral surfaces of the Fourier transform of heart sounds as a function of time and is a useful diagnostic tool both for...http://www.google.fr/patents/US5012815?utm_source=gb-gplus-shareBrevet US5012815 - Dynamic spectral phonocardiograph
