[amsat-bb] Going Digital Someday
m5aka at yahoo.co.uk
Wed Oct 22 12:07:26 UTC 2014
> Analog SSB and CW modulation in a 3U to 6U cubesat may not be practical at HEO
If that were true then it follows that the modulation currently used with Codec2 Digital Voice is not practical for HEO either.
Codec2 Digital Voice may use just over half the bandwidth of SSB but it is 100% duty cycle which which will increase the power drain on the satellite. Current Codec2 DV does not work at low signal to noise ratios - higher power would be required on the downlink to achieve satisfactory performance.
That said, it may well be that a modulation scheme can be developed that can deliver a reasonable data rate to support speech, say 1600-2400 bps, at a low S/N (<10 dB) while not being critical on tuning.
73 Trevor M5AKA
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