); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY
On Aug 1, 2007, at 0:51, Dr Bruce Griffiths wrote: >> > Henk > > There is no theory to show that sigma delta modulators of order higher > than 2 are actually unconditionally stable. Yes, but with the Gerzon-Craven theory is is possible to predict stability of noise shapers. My experience with Gerzon-Craven in a number of noise shapers is very good, and upto 11th order (never tried more). > Merely simulating the device is not conclusive proof that the > modulator > will never saturate, albeit infrequently. > Most implementations include saturation detection circuitry that > resets > the modulator should this occur. We use feed-forward and graceful degradation. In this way saturated noise shapers recover correct. In our application overdriven noise shapers can not be avoided at input signal transients. > If saturation isn't too frequent then for most purposes this is only a > minor annoyance. > However cascaded first order modulators as employed in the MASH > technique are stable in theory and practice. How to match analog circuits with digital circuits for the mash, that is the question. How do you avoid leakage? > However if one adopts a non linear control theory approach, one can > actually design high order modulators that both stable in theory > and in > practice. Unconditionally? Do you have a link for me? Henk _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
