That is exactly how the Drake SP75 speech processor works - Hank K7HP
> You connect your microphone audio to a little AM or DSB generator,
> working at some frequency such as 455 kHz. Then you compress or even
> clip that signal to increase the average power output. Probably goes
> though some bandwidth limiting filters. After that it gets demodulated
> back to audio, and feeds the microphone input of the SSB rig. Since the
> compression/clipping/whatever is done at some "intermediate frequency"
> and then demodulated back down to audio, the IMD "splatter" and
> harmonics that are generated, don't get transmitted. Only bandwidth
> limited audio goes to the microphone input of the SSB transmitter, and
> the SSB transmitter audio stages and RF stages are never driven into
> non-linearity. The transmitted signal bandwidth is limited by the usual
> crystal or mechanical filters. You get a really dense high average power
> signal.
>
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