Is there a relation between the dead zone of sigma delta modulator and filter order? This question refers to the link https://pure.tue.nl/ws/portalfiles/portal/1546321/521243.pdf. In chapter 4 it discusses the topic of dead zone, which appears in the delta sigma modulator. Dead zone means that when input signal to the modulator is very small than the output of the modulator will not follow the input, for small input signal the output of the modulator depends on the state of the modulator. The input must be higher than the dead zone to break the repetative pattern of the modulator.

The question: How the the dead zone is related to the filter order of the modulator? In the link it shows for first order filter but not much is written about higher order modulator and dead zone.
From the paper you link to:


  Modulators with a  higher order loop filter also exhibit a  dead-zone which can be calculated in a  similar manner. Because of the higher gain in the loop filter, the dead-zone of these modulators will be considerably smaller than the dead-zone of the first order SDM*. Very small signals (including system noise) will disturb the idle patterns of such SDMs, rendering the dead-zone undetectable in practical implementations. 


And if you had a situation where system noise didn't disturb the idle patterns that cause dead zones, you could always inject some dither that's intentionally designed to have its spectral content at high frequencies.

* SDM = sigma delta modulator, in that paper's nomenclature.