Sigma-Delta MOD1: Quantizer gain

[neoflash]

In text books, the MOD1 z-domain model assumed quantizer gain as 1 for analysis.
Is this correct?

What if the gain is different from 1, any analysis done there?

 

[neoflash]

also another question, 2nd order MOD suffer spur, why not 1st order?

 

[naalald]

Hi,
Yes, and it also may be sth else.
This paper may help you (esp. see appendix A).

 

[Yanhui]

In text books, the MOD1 z-domain model assumed quantizer gain as 1 for analysis.
Is this correct?

What if the gain is different from 1, any analysis done there?

Y(z)=[U(z)-V(z)*z^(-1)]/[1-z^(-1)]

if the gain is different
Y(z)=[U(z)*gain1-V(z)*z^(-1)*gain2]/[1-z^(-1)]
as gain1=gain2=1, u can get the structure of this figure

 

[caosl]

set the quantizer's gain is 1 can make analysis easier, and some the main conclusions canbe drawed. But in fact the gain is not 1 in 1-bit quantizer,
the exactly value must through simulation, then calculate it,.you can refer to
the book: "Understanding the delta sigma data converter"