Questions about using SD Toolbox

[rhayne]

Good day.

I'm a beginner in designing Delta-Sigma ADCs and I stumbled upon the SDtoolbox in Mathworks. As I try to implement the various demos included(SD2demo.m to be exact), I began to notice the following:

bw=22.05e3; % Base-band
R=256;
Fs=R*2*bw; % Oversampling frequency
Ts=1/Fs;
N=2^14; % Samples number, originally 2^14
nper=17;
Fin=nper*Fs/N; % Input signal frequency (Fin = nper*Fs/N)
Ampl=0.2-pi/256; % Input signal amplitude [V]
Ntransient=10;

So my question is, how do I interpret what nper and N are? What is their use? Why not use the input frequency of the desired signal instead? Also, what is the baseband? why use it for computing the oversampling frequency? As I recall, the oversampling frequency is the nyquist frequency multiplied to a certain oversampling ratio(which is in this case, R).

Thank you and I hope to hear your thoughts on this.

 

[rhayne]

help please. this is really important