Stuart Longland VK4MSL
On 15/05/17 14:57, Konrad Roeder -- WA4OSH wrote:
Can a UDRC hat be used for FreeDV?[…]
It should work. It is actually on my TODO list to get my little
Raspberry Pi going with FreeDV.
At worst, we might need to tell it how to drive PTT, and that should not
be a hard modification.
Why FreeDV on a Raspberry Pi with a UDRC "hat"?Actually, Codec2 does pretty good and compares favourably to AMBE/IMBE.
It also gives MELPe 600 a run for its money.
That said, the UDRC is fundamentally not much different to the USB codec
dongle. Where it has a significant edge over the USB dongle is:
- GPIO integration for PTT
- I²S is less CPU intensive than USB
- better RF hardening
You still need to do the FEC/trellis coding/modulation *ON* the CPU.
UDRC won't do that for you. It may be possible to also do some
modulation using the GPU as a poor man's DSP.
The other option is replacing the TI TLV320AIC3204 chip with the '3254,
which has some DSP capability built-in, although how good that is for
modems is anyone's guess.
Stuart Longland (aka Redhatter, VK4MSL)
I haven't lost my mind...
...it's backed up on a tape somewhere.