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From: jbuck@galileo.berkeley.edu (Joe Buck)
Newsgroups: comp.dsp
Subject: Re: US Gov. sends real-time audio at 2400 baud!
Message-ID: <39484@ucbvax.BERKELEY.EDU>
Date: 9 Nov 90 18:31:59 GMT
References: <1990Nov8.210640.2893@ux1.cso.uiuc.edu> <PITARO.90Nov9085439@sleepy.uucp>
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Reply-To: jbuck@galileo.berkeley.edu (Joe Buck)
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In article <PITARO.90Nov9085439@sleepy.uucp>, pitaro@rocket.uucp (Michael Pitaro) writes:
|> An example of a secure telephone is a STU III.  It uses 1200 bps
|> LPC10-E for voice compression followed by encryption and a
|> REED-SOLOMON block code for error recovery.  The voice quality is poor
|> but intelligible.  I understand the government is going to upgrade the
|> STU III to use 2400 bps CELP voice compression.  Motorola sells one
|> version of the STU III.  I hear ATT sells another version.

Correct except that your rates are off by a factor of two.  The LPC10-E
algorithm is 2400 bps; the federal standard CELP algorithm is 4800bps.

--
Joe Buck
jbuck@galileo.berkeley.edu	 {uunet,ucbvax}!galileo.berkeley.edu!jbuck