A question about CLANS in delsig (delta sigma toolbox)

[raceon1600]

clans delta sigma toolbox

Hi.
I have problem with CLANS in delsig tolbox. I cant understand what is the "Q"?

ntf = clans(order=4,R=64,Q=5,rmax=0.95,opt=0)

In the pdf file of this toolbox it is written that "The maximum number of quantization levels used by the fed-back quantization noise."

But I vant understand it!!!

If I have 4 bit quantizerm what is the value of Q?

 

[mr_chip]

clans toolbox

I would say that for 4-but internal DAC you will have Q=2^4=16, but I suggest you doublecheck toolbox documentation, it's been a long time since I used it myself..

 

[PoojanWagh]

Going through the toolbox, it seems that Q does *not* refer to the number of quantization levels, but the out-of-band gain. In the Schrier et al yellow book, they recommend a value of 3.5 dB (1.5 V/V) gain at Fs/2 for the NTF. Indeed, the default value digging deeper into the scripts is 1.5 V/V.

I am unfamiliar with the paper cited in the documentation for this clans function. However, it does say that Q = |H| - 1, so it would seem to me to refer to some gain metric on the noise response (or maybe the noise shaping filter).