Title :
Mismatch cancellation for complex bandpass sigma-delta modulators
Author :
Yu, Li ; Snelgrove, Martin
Author_Institution :
Dept. of Electron., Carleton Univ., Ottawa, Ont., Canada
Abstract :
The performance of complex sigma-delta A/Ds can suffer due to mismatches in the hardware as well as phase and gain errors introduced at the RF front-end. Improving the resulting SNR is essential. This paper presents a method that uses DSP techniques to filter out the mismatch and the RF errors. Results of applying an adaptive complex LMS filter to a fourth-order bandpass sigma delta modulator are presented that show an improvement in SNR of 15~20 dB
Keywords :
adaptive filters; frequency response; least mean squares methods; sigma-delta modulation; DSP techniques; RF errors; SNR; adaptive complex LMS filter; complex bandpass sigma-delta modulators; fourth-order modulator; gain errors; mismatch cancellation; phase errors; Band pass filters; Circuit noise; Degradation; Delta-sigma modulation; Equations; Frequency; Least squares approximation; Noise shaping; Signal to noise ratio; Transfer functions;
Conference_Titel :
Circuits and Systems, 1997. Proceedings of the 40th Midwest Symposium on
Conference_Location :
Sacramento, CA
Print_ISBN :
0-7803-3694-1
DOI :
10.1109/MWSCAS.1997.662199
