Title :
On the design of high-performance wide-band continuous-time sigma-delta converters using numerical optimization
Author :
Loeda, Sebastian ; Reekie, H. Martin ; Mulgrew, Bernard
Author_Institution :
Sch. of Eng. & Electron., Univ. of Edinburgh, UK
fDate :
4/1/2006 12:00:00 AM
Abstract :
Continuous-time (CT) sigma-delta (ΣΔ) modulators are growing increasingly popular in wide-band analog-digital conversion. High orders of quantization noise shaping, and multibit quantizers, are used to compensate for the low oversampling ratios in wide-band applications. These, however, add circuit complexities and excess loop delay that are detrimental to the ΣΔ control loop. This paper presents an exact mathematical analysis technique, based on the CT-discrete time equivalence, that can take these effects into account. A design-by-optimization approach based on that analysis is used to compensate for these effects, avoid intractability issues and to gain flexibility in the design. It is also shown that it is advantageous not to fix the position of the quantization noise-shaping zeros in the signal band.
Keywords :
circuit optimisation; continuous time systems; quantisation (signal); sigma-delta modulation; CT-discrete time equivalence; continuous-time sigma-delta converter; design-by-optimization; numerical optimization; quantization noise-shaping zero; wide-band sigma-delta converter; Circuits; Complexity theory; Computed tomography; Delay; Design optimization; Filters; Noise shaping; Quantization; Sampling methods; Wideband; CT–discrete-time (DT) equivalence; Continuous-time (CT) sigma–delta (; design by optimization; impulse invariance;
Journal_Title :
Circuits and Systems I: Regular Papers, IEEE Transactions on
DOI :
10.1109/TCSI.2005.860116