lemaster at verizon.net
Sun Nov 27 19:01:50 CST 2005
AMBE is from Digital Voice Systems.
They have voice samples on their page. Unfortunately the high rate
samples seem to have a broken link.
AMBE compression is used in Iridium, APCO 25 digital radios,
and the ham project designed by G4GUO some years ago. G4GUO's design
used a Motorola telephone exchange codec which outputs 8 bit mu law
and is then compressed by a DVS ASIC. I don't know how much the
ICOM version differs from the original, if any, in the voice coding
section. Dave Borden and I started to build up two systems
before he moved away. The system was described in QEX.
AMBE is considered by some to be the best available at very
low data rates, 2 and 4 kbps. And, it's a codec available
in small quantities that (at least at on time) hams could get.
You might run AMBE at a faster data rate but at a few kbps it is
difficult to get natural sounding speech.
From: tacos-bounces+lemaster=verizon.net at amrad.org
[mailto:tacos-bounces+lemaster=verizon.net at amrad.org] On Behalf Of A.
Sent: Sunday, November 27, 2005 6:06 PM
Anyone have some .WAV files from an XM Radio?
I just saw a comment on AMBE (the codec used in the ICOM D-STAR):
"We are currently using AMBE (4Kbps) for our Traffic/Weather Channels.
If you have ever had a chance to hear the service, you will know that
AMBE does not do us well."
- Terry Carr
Manager, Broadcast Applications
XM SATELLITE RADIO
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