Medical Definition of Phonocardiograph
1.
An instrument, utilizing microphones, amplifiers, and filters, for graphically recording the heart sounds, which are displayed on an oscilloscope or analog tracing.
Linear phonocardiograph, a phonocardiograph that records all chest wall vibrations resulting from cardiac activity, with emphasis on low frequency vibrations due to its filter characteristics.
Logarithmic phonocardiograph, a phonocardiograph that records only theoretically audible vibrations with emphasis on the higher frequencies due to filter characteristics designed to imitate the logarithmic frequency-intensity response of the human auditory apparatus.
Spectral phonocardiograph, an instrument for recording the heart sounds in which the electrical changes created by the latter pass from a microphone through a series of filters, each of which is tuned to a particular frequency band; output from each filter activates a separate light source of brightness proportional to the intensity of the sound transmitted through that filter; the lights are arranged vertically in descending order of frequencies. A record is obtained by photographing the vertical row of lights.
Stethoscopic phonocardiograph, a phonocardiograph that records all sound vibrations, audible and inaudible, conveyed by the stethoscope; however, very low frequency vibrations (in the range of body movements) are filtered out.
(05 Mar 2000)
Lexicographical Neighbors of Phonocardiograph
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