DELTA-SIGMA MODULATOR, ELECTRONIC APPARATUS AND METHOD FOR CONTROLLING DELTA-SIGMA MODULATOR

摘要

The present invention effectively suppresses idle tones in a delta-sigma modulator that generates a feedback signal using a digital-to-analog converter. A filter integrates a difference between an input analog signal and a feedback signal and outputs a resultant signal as an integral signal. A preceding-stage quantizer quantizes the integral signal into a digital signal and outputs the digital signal as a preceding-stage output signal. An adder adds a prescribed dithering signal to the preceding-stage output signal and outputs a resultant signal as a subsequent-stage input signal. A subsequent-stage quantizer quantizes the subsequent-stage input signal into a digital signal having a smaller number of bits than the preceding-stage output signal and outputs the digital signal as a subsequent-stage output signal. The digital-to-analog converter converts the subsequent-stage output signal into an analog signal and outputs the analog signal to the filter as a feedback signal.