The analysis and control of random channel errors in an adaptive delta modulation system

Due to the nonlinear nature of adaptive delta modulation (ADM) systems, mathematical analysis has been somewhat limited. In this paper the effects of channel errors on the decoded ADM signal are studied. By using the characteristics of an all-digital ADM, a mathematical model which clearly shows the effects of bit errors is developed. It is observed that the decoded error signal exhibits both a DC and an AC component. It is shown that the DC error can be controlled with a leaky accumulator and the appropriate output filter. By studying the form of the AC error it is possible to control excessive signal distortion, particularly for the case of high bit error rates. As a conclusion, the computer simulation results are presented to verify the analysis and error control with a variety of test signals.