Optimum Coherent Linear Demodulation

Presented is the performance analysis for four types of linear-modulated communication systems where the message to be transmitted comes from one of two classes of stochastic processes, and the additive channel noise is white and Gaussian. The two classes of stochastic processes which are used to modulate the transmitter are taken to be the "maximally flat" and "asymptotically Gaussian" processes. Demodulation is accomplished at the receiver by coherent frequency translation using a noisy replica of the carrier and filtering the result with one of two types of Wiener filters. These are commonly referred to as the zero-lag (realizable) and infinite-lag (nonrealizable) Wiener filters. The four types of modulation considered are: linear-modulation, double-sideband (DSB); linear-modulation, double-sideband, suppressed carrier (DSB/SC); linear-modulation, single-sideband (SSB); and linear-modulation, single-sideband, suppressed carrier (SSB/SC).