Brainstorming (no code, no circuit boards):
If we are talking VHF (hopefully) then probably the 3200 vocoder is a better
choice to get a better voice quality. This is 64 bits 50 times a second (20 ms
frames). But that's just the voice. Obviously you want data and protocol as
well.
Say a protocol handshake to get started, separated from the stream protocol.
That is, two ends negotiate a connection, and then the stream starts. Some
signal to end the stream. You could negotiate half or full duplex, simplex or
repeater.
The stream would be some number of voice and data packets while the PTT is
enabled.
64 bit voice + 64 bit data, or 128 bits every 20 ms. That would be 64 QPSK OFDM
carriers, or 128 BPSK carriers, then you would need some guard time so the
transmitter can ramp up and down. You could send 4 of these OFDM signals every
slot, centered on the 100 ms slot time. Obviously some delay buffering before
the next slot time.
Whatever that equals as far as sending the OFDM carriers at whatever bit-rate.
Hopefully Less than 5 kHz for SSB and 10 kHz for FM. Obviously wider than an
analog 3-3.5 kHz modulator.
73, Steve
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Freetel-codec2 mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/freetel-codec2
