Keyed pilot SSB - An alternative system for VHF mobile radio

Present experimental SSB systems for VHF mobile require product demodulation and phase lock to a reference pilot tone. An alternative system is proposed which requires no phase lock and involves only baseband processing. Acquisition problems are avoided and receiver tuning is non-critical. No frequency shift of the demodulated signal takes place with receiver mis-tuning, maintaining naturalness and permitting tone signalling and data transmission.