Demodulation of Single-Sideband Signals Via Envelope Detection

Present day single-sideband (SSB) technology is based on synchronous demodulation, with implicit stringent stability requirements. This factor has deterred the use of SSB in some services in which it might be advantageous. There are two general ways to mitigate the stability problem: by transmitting a pilot carrier to synchronize a local oscillator, and by extracting the information signal from the envelope of the SSB signal. This paper deals with the second approach, i.e., SSB reception via envelope detection. It is shown both theoretically and experimentally that distortionless reception is possible if a carrier component of a certain minimal strength is present, and if special circuitry is provided to process the SSB envelope. An interesting and possibly useful system based on these premises is described.