Re: SSB decoding in SDRs and as procedure (algorithm) in the digital software


jim_kr1s <jkearman@...>
 


--- In ultralightdx@..., "Wolfgang H" >
> Hallo Jim,
>
> as far as I understood the technique of decoding SSB, there is a relationship to AM-decoding.
>
> In AM, the software-author takes two signal parts of the total AM-signal after decoding and adds it to an AM-signal. The software seems to take mainly the LSB and the USB signal part and after this, for AM are LSB and USB added in the right phase situation, to "produce" AM.

Hi, Wolfgang,

I was assuming the G3 wasn't a DSP radio. I agree, DSP SSB demodulation would be more stable than using a separate BFO. The control chip would have to do more work, though. For SSB I think you want a tuning resolution of at least 50 Hz. I don't know how they do that on the G3. The Sony 7600GR has a continuous BFO adjustment, plus-or=minus 5 kHz, I think. But I was told it drifts, so it is probably analog. I guess you could switch in a second, "fine tuning" shaft encoder or rocker switch in SSB mode, that would reset to zero offset when you adjusted the main tuning encoder.

73,

Jim, KR1S
http://qrp.kearman.com/ 

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