From: Thomas Sailer (nnewexvy.diys@uniroma1.it)
Date: Sun Jan 07 2001 - 19:09:41 EET
Tomi Manninen wrote:
> That is true. But it might be a nice experiment to try newqpsk with an FM
> radio. One could potentially get 3000bps or even more through mic/speaker
> connectors. On FM the tune preamble could be dropped and the sync preamble
> probably shortened. Unfortunately that isn't currently implemented in my
> code but if someone is interested I could do that.
If you want to maximize the bitrate with AFSK handhelds over the MIC port,
you may also use the pskmodem code, which was actually designed for this
application. It does about 7kbit/s and I've tested it using two Standard
handhelds, which have the worst frequency response according to
DF9IC's measurements. The downside is the code only works with 9.6kSamples/s
samplerate and it is computationally quite expensive due to a viterbi
equalizer for the 8PSK constellation. But enabling MMX support (and
an MMX capable CPU) help...
Tom
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