Implementing RZ-SSB reception
I'm still learning about SDR software available. I'm wondering, do any offer RZ-SSB reception like this is talking about?
It ought to be possible for SDR software to auto scan the received signals for any accidental or deleberate in phone signal spurs, like within a 3KHz SSB signal, and use those as pilot tones for implementing a RZ-SSB decode of the signal with the lower noise anti fading improvements it offers.
For example, if I'm in the US and I pickup a SSB phone signal from a country with 50Hz AC power then that transmitted signal might have some embedded signals at 50Hz, 100Hz, 200Hz, etc. Else, if a Weaver method was used to transmit a SSB signal then it might have some leakage of the tone to the 2nd set of IQ mixers that could be used as a pilot tone. If the SDR software can lock into those then they could be used to implement RZ-SSB decoding. The inserted tones would need to be spun around the Waever frequency so ought to be inserted right along with the audio to be split into I and Q for transmission.
Transmitters could also purposely insert additional pilot tones and SDR GUIs could allow the user to select what tone frequencies to insert along with the phone signal.