Hi neoflash,

The quantizer gain can only be assumed to be 1 for multibit quantizers and for reasonably large signal swing at quantizer inputs.

As far as I know, the quantizer gain needs to be calculated from the signal statistics for a 1-bit quantizer.
And the textbooks also do it this very way. I would recommend that you look at the textbook by Schreier &
Temes or the TCAS paper by Baird & Fiez.

Regards
Vivek

Which z-model do you mean???

If it assumes a gain of 1, then there is the general assumption that the quantizer
is not being overloaded. For a 1-bit quantizer, I would suggest that one still does
not set the gain blindly to 1. However, it is probably used because it is easy to set
it to 1. The references I mentioned cover the topic in greater detail.

Regards
Vivek