Abstract

A method and apparatus for transposition of heart sounds to a range easily detectable by the human ear and suitable for transmission, for discrimination of low intensity or brief sounds, and for display of the heart sounds on conventional recording devices involve steps of and means for, respectively, converting the heart sounds to electrical signals having given frequency components, providing an audio frequency carrier having further frequency components, generating a transposed output representing a sum and a difference of the frequency components and the further frequency components, filtering the transposed output to remove the difference of the frequency components and further frequency components, and generating an audible representation of the heart sounds and/or displaying a visual representation thereof. As a further feature, the inventive method and apparatus provide for detection of an envelope of heart sound intensity, and provision of a visual indication of whether or not electrical signals corresponding to heart sounds are of proper signal amplitude for consistent measurement of heart sound intensity.