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From: ghot@ms.uky.edu (Allan Adler)
Newsgroups: sci.med,sci.electronics
Subject: audio and digital recording of heartbeats
Message-ID: <1991May3.055945.21510@ms.uky.edu>
Date: 3 May 91 05:59:45 GMT
Sender: ghot@ms.uky.edu (Allan Adler)
Organization: University Of Kentucky, Dept. of Math Sciences
Lines: 39


Now that I have a stethoscope to play with, it occurs to me that there
are some enhancements I would like to investigate:
(1) How can I make audio recordings of what I hear through the stethoscope ?
(2) How can I make a computer file containing what I hear through the 
    stethoscope ?

I understand that in principle, I can use some kind of microphone for (1)
and some kind of facility for transferring sound to computers, such as
is found on a sparc station. However, each method of transfer involves
some loss of information, e.g.:
(i) The limitations of the microphone, what sounds it attenuates etc.
(ii) The quality of the interface between the microphone and the stethoscope.
(iii) The quality of the interface between the computer and the microphone.
(iv) The resolution afforded by the software that converts the signals to
     digital files.

Just to be concrete, it might be that some conditions can be detected
by a human listening to the heart but that these conditions are not
detectable from listening to the recording or studying the digital
file.

I don't want to experiment or develop this technique since I am quite
certain that it has already been done. I am also certain that one can
always get very expensive versions of these things. What I am interested
in is some way of doing it for pennies. For example, has someone published
a paper on how to do it including details of construction ?

This question also impinges on the cassettes that are sold in some medical
bookstores containing recordings of heartbeats of various types. Such
cassettes are often accompanied by a text book of some kind and are
priced like most medical books. How good is what one is getting  and how
did they make the recordings ?

Please send your comments directly to me since I do not read news.
Thanks.

Allan Adler
ghot@ms.uky.edu