Patent ID: 6674381
Filing Date: 2004-01-06
Classification: H03M

Abstract:
A sigma delta modulator, comprising:a filter receiving an input signal and an analog feedback signal, the filter being adapted to provide a filtered output signal according to the input signal and the analog feedback signal; a quantizer coupled with the filter, the quantizer being adapted to provide a quantized output signal according to the filtered output signal; a digital to analog converter coupled with the filter, the digital to analog converter comprising a plurality of circuit elements, the individual circuit elements having an associated element value, the digital to analog converter being adapted to provide the analog feedback signal corresponding to the quantized output signal using circuit elements selected according to the quantized output signal, the plurality of circuit elements comprising: at least one mismatched circuit element having a mismatched element value differing from a design element value by a mismatch amount, and a plurality of matched circuit elements having element values within a tolerance amount of the design element value, the mismatch amount being greater than the tolerance amount; and a dynamic element matching system coupled with the digital to analog converter and the quantizer, the dynamic element matching system being adapted to vary the selection of circuit elements of the digital to analog converter.