Hi,

can somebody give an explanation on dead-zones in delta-sigma
modulators. Can this effect be seen in simulation?

Dead zones are a result of finite opamp gain gain in Sigma Delta Modulators. The reason that dead zones occur is because the opamp is not able to completely transfer the charge from the sampling capacitor to the integrating capacitor.

The effect of dead zones actuially results in a certain "minimum" input being present at the Modulator before it can generate a LSB so as to say. Roughly, a gain of 1/LSB(in volts) is necessary to avoid the Dead zone effect.

The post about recommends reading through the Temes book, which is an excellent source for understanding dead zones.