US Patent 7362250 Dynamic dither for sigma-delta converters

A sigma-delta converter having dynamic dithering that reduces or removes idle-channel tones and increase linearity of the converter. The dither is differentiated in multiple orders before being applied to the converter quantizer. The differentiation order and the amplitude of the dither are determined dynamically based on the input signal amplitude in order to obtain the most effectiveness of dithering. The dynamic dither can be used in both analog-to-digital and digital-to-analog converters.