Designer’s Guide Community

‹ Previous topic | Next topic ›

Pages: 1

A question about delta sigma modulators stability (Read 2370 times)

aidnaal

New Member

Offline

Posts: 4

A question about delta sigma modulators stability
Jan 03^rd, 2008, 3:17am

Hi,
In delta sigma modulators the maximum SNDR is given by the famous equation of Shreier book;

But in most cases this is not valid and the measured or simulated SNDR is below this value. In Shreier book it's said that in an unstable DS modulator the SNDR is below this value, and the unstability causes the degradation in SNDR. Could you please explain that what is the criteria for stability and how we can recognize if a modulator is stable or unstable?
Thanks a lot.

maxSNDR.JPG

IP Logged

Berti Community Fellow Offline Posts: 356	Re: A question about delta sigma modulators stabil Reply #1 - Jan 6^th, 2008, 10:16pm It is not possible to give an accurate analytical expression for the overload level (stability) of a DS modulator. However, check CLANS (NTF optimization tool), which is part of R. Schreiers DS-toolbox for matlab. There it is described how stability is determined without simulation. Regards
Back to top	IP Logged

HdrChopper Community Fellow Offline Posts: 493	Re: A question about delta sigma modulators stabil Reply #2 - Jan 20^th, 2008, 5:05pm Another extra piece of info. In that book you�ll find that stability can be predicted based on the value of the NTF as frequency approaches infinite. The criteria change depending on the modulator being single or multi bit. Regards Tosei
Back to top	Keep it simple IP Logged

Pages: 1

‹ Previous topic | Next topic ›