Title :
A single DAC CT sigma-delta modulator with Butterworth STF characteristic
Author :
Brueckner, T. ; Zorny, C. ; Mathisy, W. ; Ortmanns, Maurits
Author_Institution :
Inst. of Microelectron., Univ. of Ulm, Ulm, Germany
Abstract :
In this paper a continuous time Sigma-Delta modulator filter structure is proposed, which combines the known feed forward structure and an excess loop delay (ELD) compensation technique in order to realize an ELD compensated modulator with Butterworth signal transfer characteristic, which employs only one digital to analog converter (DAC) in the feedback path. A mapping strategy for the coefficient values is given and an exemplary modulator is evaluated through simulation. It is compared to a modulator with feed forward filter structure and an additional feedback path for ELD compensation. Furthermore an investigation on the sensitivity to coefficient variation is presented.
Keywords :
Butterworth filters; compensation; continuous time filters; digital-analogue conversion; sigma-delta modulation; Butterworth STF characteristic; Butterworth signal transfer characteristic; ELD compensation technique; continuous time sigma-delta modulator filter structure; digital-to-analog converter; excess loop delay compensation technique; feed forward filter structure; mapping strategy; single-DAC CT sigma-delta modulator; CMOS integrated circuits; Hardware;
Conference_Titel :
Circuits and Systems (MWSCAS), 2011 IEEE 54th International Midwest Symposium on
Conference_Location :
Seoul
Print_ISBN :
978-1-61284-856-3
Electronic_ISBN :
1548-3746
DOI :
10.1109/MWSCAS.2011.6026359
