Title :
A MASH modulator with digital correction for amplifier finite gain effects and C-ratio matching errors
Author :
Davis, Alan J. ; Fischer, Godi
Author_Institution :
Weapon Syst. Dept., Naval Underwater Syst. Center, Newport, RI, USA
Abstract :
An alternative approach to remove the effects of amplifier finite gain and C-ratio mismatches encountered in a MASH delta-sigma modulator is presented. By adding a digital correction term to the output of the digital noise cancelation filter, the parasitic quantization noise terms can be removed for all but the final stage, eliminating the lower-order quantization noise terms due to non-ideal integrators. Using this technique, the MASH can approach the performance of an ideal 3rd order modulator. We have confirmed an SNR+THD of 105.6 dB via a behavioral simulation of the MASH using an amplifier open-loop gain of only 500 and capacitor matching errors as large as of 1.0%
Keywords :
error correction; interference suppression; quantisation (signal); sigma-delta modulation; 105.6 dB; C-ratio matching errors; MASH delta-sigma modulator; amplifier finite gain effects; behavioral simulation; capacitor matching errors; digital correction; digital noise cancelation filter; open-loop gain; parasitic quantization noise; Bandwidth; Capacitors; Circuit noise; Delta modulation; Digital modulation; Dynamic range; Filters; Multi-stage noise shaping; Noise cancellation; Quantization;
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.1997.666073
