A delta modulation filter for speech-type signals

This paper considers the realization of an all-digital system for direct filtering of a delta modulation (DM) encoded signal. It is shown (1) that this system can be realized fairly easily for any type of filter function when the signals are encoded with a linear DM. The problem of digitally filtering an adaptive DM (ADM) encoded signal is considered. In addition, a circuit realization that does not require complex digital hardware is outlined. Performance has been tested via simulation on a digital computer, using a variety of test signals; both temporal and spectral results are presented.