Constructing Parity bits for IMBE data?

[bdk]

Hello,

I have a data source sending 88 bit IMBE frames which I want to decode with a DVSI VC55 Decoder board, but the decoder board only supports the 144 bit IMBE frame format with the extra 56 bits of Parity data present. The data I have has apparently already had the FEC applied / stripped.

I pinged DVSI support on this and they pointed me at the TIA-102 spec and told me to implement the FEC algorithm to restore the parity bits. Before I dig up a copy of that spec and start coding, I was hoping an implementation of this already existed. I took a look at libmbe, but unless I'm misunderstanding the code, it seems to only contain the code for the inverse transformation ( removing the parity to get the 88 bit representation).

Thanks in advance for any insight anyone can provide.

 

[SCPD]

I took a look at libmbe, but unless I'm misunderstanding the code, it seems to only contain the code for the inverse transformation ( removing the parity to get the 88 bit representation).

The IMBE codec in op25 is fully bi-directional, so I'm told.

Alternatively, you could inject the post-FEC IMBE frames directly into mbelib and throw your VC55 away.

 

[bdk]

Thanks,

I'm able to decode with mbelib, but I'm still interesting in getting this VC board to work

Anyone have a lead on the OP25 source? My partner on this project joined the dev list and requested access to the SVN repository a couple of weeks ago, but they seem to be having server issues.

 

[MattSR]

The server was temporarily down and SVN access has been since been granted to all that have requested.