Jonathan, >From the protocol:
"The error correction signal is interleaved with the packet data with a signaling rate of 1/2, a folding length of 3, and a depth of interleave of 24," You are correct and I stand corrected. It's been a while since I read it. Only the header has interleaving and if a voice frame fails correction it is repeated for the next 20 ms until a new decode is attempted. Every 21st data frame has a sync pattern for training. Thanks for the peer review, Craig --- In [email protected], "Jonathan Naylor" <naylo...@...> wrote: > > Hi Craig > > > This contrained the final (4800 bps/6.25 kHz) air interface to a 2400 bps > > AMBE perceptual coder with 2/3 convolutional FEC. This left about ~1kilo > > bit a second of data on the air interface for usage as data (as any user > > saw fit!). > > You're a little wrong here. D-Star uses the AMBE codec in block FEC mode. The > FEC used is two blocks of Golay (24,12,8) with the remaining 24 bits > unprotected. I presume this latter block is of less significant bits that can > sustain corruption with relatively little impairment of the carried speech. > > Jonathan G4KLX >
