Does OP25 have any capability for Phase 2 at the moment?
I've seen a couple things suggesting that various people have been working on it for a few years now, but nothing solid about what progress has been made. Just curious, as I have a few systems here turning on that are looking like they will be speaking phase 2.
Thanks, Matt.
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
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@yahoo.com wrote:
Hi Matt
Two things
- 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.
- 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
-
ikj1234i＠yahoo.com -
Matt Mills