Only the Coherent QPSK modem "cohpsk" requires 7500, but it include a rate conversion software to/from 8000. It has a lot of FIR table constants, and the 700 codec also has a lot of quantization constants. It will need a lot of memory using a sound card. The other 700 modes (FSK, FDMDV, and OFDM) just use 8000. I think 3200 and 2400 do fine at 8000.
On PC's the sound cards really prefer high sample rates like 48k, with 48k being easily rate converted, but with firmware, you can use an A/D D/A at lower rates. 7500 or 8000 on firmware and you don't have to rate convert like on a PC single chip sound card. 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 Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
