Patent ID: 7209796

Claim:
An auscultatory training apparatus comprising: a playback system; a computer having memory means for digitally storing a database of pre-recorded, physiological sounds for playing on the playback system, means for selecting one of the pre-recorded sounds for playback, means for generating an input digital signal of the sound selected for playback, a digital to analog converter for converting the digital signal into an input analog signal, an analog to digital converter to receive an analog output signal from the playback system and convert the output signal to a digital signal, and reconstruction means for reconstructing the input digital signal so as to cancel the distortions of the playback system for accurate audible reconstruction of the sound in the playback system, wherein the reconstruction means comprises an inverse model of the playback system in the form of a digital infinite impulse response filter; and the playback system including an amplifier for receiving and amplifying the input analog signal from the digital to analog converter, an output speaker connected to the amplifier for converting the analog signal received from the amplifier into an audible reconstruction of the selected sound, an elongate tubular member positioned proximate the speaker so that sound from the speaker travels through the tubular member, a listening mechanism operatively coupled to the tubular member to enable a user to listen to the reconstructed sound, and a microphone mounted on the tubular member and connected to the analog to digital converter, the microphone operable to convert the audible sound into an output analog signal and transmit the output signal to the analog to digital converter.