A possibility of compatible single-sideband transmission for long-wave, medium-wave and short-wave broadcasting

A modulation system suggested by Logan and Schroeder (1962) is investigated, in which the modulated signal occupies only the bandwidth of the message, whereas the envelope contains the message in the intelligence band and any distortion outside the intelligence band. Distortionless detection is possible with a linear envelope detector followed by low-pass filtering. The function of the envelope and the spectrum of the signal are given for single-tone modulation and are compared with conventional single-sideband transmission with carrier. As there is no known closed form solution for the nonlinear convolution integral equations describing this modulation system, it is computer-simulated by means of an iteration method. The results yield information about important system parameters for the construction of a signal processor utilizing this method. The results of the simulation are verified by measurements.