Nonadaptive DPCM Transmission of Monochrome Pictures Over Noisy Communication Channels

The present study is a sequel to the authors' 1972 paper [1] where the output signal-to-noise ratio SNR
o
is obtained for nonadaptive differential pulse-code modulation (DPCM) systems with an arbitrary linear predictor operating on noisy digital channels. Important stability constraints for an arbitrary linear predictor are obtained. A complete analytical study of previous line-line-and-sample feedback systems is presented. The SNR
o
improvement over previoussample feedback is found to increase from approximately 2.6 dB for error-free channels to 4.1 dB for noisy channels. Optimization of the predictor for noisy channel usage is shown to greatly reduce the sensitivity of SNR
o
to variations in message and channel parameters, while use of the resulting predictor on error-free channels yields SNR
o
values which are almost as good as those obtained when the predictor is optimized for error-free channels. Reduction of the effects of digital channel errors on SNR
o
using various methods, including periodic or pseudorandom resetting are considered briefly. Hardcopy results from computer-simulated DPCM monochrome image transmission systems corroborate our analytical results.