Analog-to-Digital Conversion by Means of Delta Modulation

It is shown that normal delta modulation can be used for the transmission of dc signals. A circuit is described in which a delta modulator is combined with a counter for analog-to-digital conversion of a dc signal. Several factors contributing to the accuracy are developed. One of these factors which has not been dealt with previously is the size of the steps in the reconstructed signal due to the finite integrator time constant. Two examples of delta modulators are described; one of them a high precision system, the other a simple design of moderate precision.