Digital to analog conversion system with the addition of dither to the

Abstract

A system for converting an audio or like data signal from digital to analog form, with the addition of dither (white noise) to the digital input, with or without the subsequent removal of the dither from the analog output, for the reduction of quantization noise. Included is a network of n adders, equal in number to the n bits of the coded data signal, for adding in bit parallel form the digital data signal and the digital dither signal. Generated by an analog dither generator, the dither signal is transformed by an analog to digital converter into an m bit coded digital output, m being less than n, prior to delivery to the adder network. Some, preferably all, of the m bits of the digital dither signal are each added to, for example, two different ones of the n bits of the digital data signal so that, for instance, an eight bits analog to digital converter can be used for the provision of a digital dither signal to be added to a 16 bits digital audio signal. The adder network is connected to a digital to analog converter for converting the bit parallel addition of the data and dither signals into analog form.