Newsgroups: comp.speech
Path: pavo.csi.cam.ac.uk!warwick!uknet!pipex!uunet!zaphod.mps.ohio-state.edu!darwin.sura.net!sgiblab!a2i!davidj
From: davidj@rahul.net (David Josephson)
Subject: SPC coding of speech in noise
Message-ID: <C70964.8sp@rahul.net>
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Organization: a2i network
Date: Fri, 14 May 1993 07:08:27 GMT
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Greetings,

Working on a system recently with SPC coding of speech 
for a compressed audio link uncovered a strange problem
that I hadn't thought about before. The pitch-tracking
algorithm normally tracks the speaker's voice correctly,
except in the presence of tones near that frequency range.
In the reconstructed audio, the pitch solution is indeterminate
and both the voice and the tone sound very strange, as might
be expected.

In this case the source of the tone was a nearby computer
fan with a fundamental around 250 Hz.

Any more robust solutions to pitch encoding that will
understand multiple non-harmonically-related spectral lines?

Cheers
David Josephson

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