Method and apparatus for dithering idle channel tones in delta-sigma analog-to-digital converters

摘要

A method and apparatus for dithering idle channel tones in delta-sigma converters is provided. In a delta-sigma modulator (10), random dither signal (23) is added before quantizing a signal in order to attenuate the idle channel tones. A random number generator (50) coupled to a digital-to-analog converter (52) with an applied biasing current (54) produces the dither signal (23). The dither signal (23) combines with an input signal at the input of a quantizer (14) in order to randomly change the quantizer output (15) and attenuate idle channel tones.