A design procedure for finding optimal fifth order Sigma-Delta modulator loopfilters

摘要

In this paper we present the results obtained in our search for stable high performance single bit sigma-delta modulator loopfilter transfer functions. The results presented are made for fifth order modulators and give the performance impact on them when varying both poles and zeroes of the transfer function. This loopfilter function search is done with fast theoretical calculation of signal to noise ratio without need of simulations and combined with theory that gives approximated value for modulator's maximal stable DC input signal.