Abstract: An analog-to-digital and digital-to-analog conversion system utilizes a modified delta modulation technique, together with generation of a number of linear waveforms forming a piecewise linear approximation of an analog signal to be encoded and decoded, to digitize the analog signal as a pulse train and subsequently retrieve an approximation of the original analog signal from the pulse train. The system comprises encoder and decoder sections of near identical structure. The encoder section includes compare circuits that compare the signal to be encoded to a reference signal and generate therefrom a binary indication of such comparisons. Successive ones of the binary indications form the digital pulse train containing information later used to approximate the analog signal being digitized.