Max,
Thanks for the update. I have a Phase 2 system that is supposed to go live
near me soon, I will attempt to capture and provide some samples with both
the control channel and voice channels.
Thanks,
Matt.
On Tue, Feb 4, 2014 at 11:50 AM, <ikj1234i(a)yahoo.com> wrote:
Hi Matt
Two things
1. We're currently working on it (as are other groups, AFAIK) - parts of
the Phase II TX/RX code have already been checked into svn and git (look
for the tdma/ directory). At this time the code that is present there
covers the decode and encode processes only partially, and it's more or
less batch-mode only. That is it will generate the set of AMBE voice code
words given a pre-captured file of samples. More work will be needed to
reduce the voice codewords into the voice model parameters so that our
existing IMBE vocoders can work with it. It turns out that both AMBE and
IMBE are distinct front end layers on a common backend which we already
have - this is because both of these codecs are members of the common MBE
family and both use the same speech model with only the parameter
quantization front ends being different.
2. One user has provided some sample captures which have been very useful
- but more samples would help greatly. In particular it would be good to
get samples which contain both the trunk control channel and the dicrete P2
voice channel at the same time. Further out it would also be good to
obtain captures of the uplink transmissions, which use a different
modulation format. That work is still pretty far off, however...
Thanks
Max