FM/FM Preemphasis Schedule Design for Concurrent All Channel Dropout and Minimum Transmission Bandwidth

Abstract

This work is concerned with the design of the FM/FM preemphasis schedule such that all channel dropout occurs concurrently in that threshold is reached at the same signal-to noise ratio at the same time in all the channels. That is, threshold occurs in the carrier IF at the same time as threshold occurs in all the subcarrier bandpass filters. This design assures that this is the minimum transmission bandwidth achievable with no channel in threshold. The procedure developed is a systematic approach to the design of the preemphasis schedule that is readily converted to an algorithmic code. When the code is implemented on a computer, the preemphasis schedule may be modified and studied for various anticipated operational parameters such as carrier-to-noise ratio at the receiver and the D(si)'s. The impact on the output signal-to-noise ratios by the specified D(si)'s can also be evaluated. A design examples is given.