Oversampling digital-to-analog converter with auto-muting feature

摘要

An oversampling digital-to-analog converter is provided with an auto-muting circuit which reduces noise in an analog output signal when a digital input signal remains at zero. Auto-muting circuit includes an input reference level code detection section which detects an input reference level code in the digital input signal. An output reference level code in a modulated output generated from an oversampling modulator is detected by an output reference level code detection section provided in the auto-muting circuit. A modulated output alteration section is provided which operates in response to the result of the detections to selectively pass the modulated output without any alteration or alter the modulated output by substituting it with output reference level codes.