Delta Sigma toolbox by Richard Schreier

Hi all,

i know there is a toolbox created by Richard Schreier (delsig.zip in mathwork). currently i am trying to use it, but i found the simulation i got is different from what the author did in his book (page 264, 265). i use the exactly the same code he provided but the output waveforms are different and the SNR values are also different.

is there any one tried this toolbox and really used it in your design works? is the toolbox reliable? any limitation i should pay attention?

thanks in advance and please share your experience if you have.

btw, i would like to discuss this toolbox more if anybody here is using it right now.

Re: Delta Sigma Question

Hi
I use the toolbox when designing. I actually don't use all the optimization functions, but I don't have problem and consider it reliable.
Could you post details (architecture schematic, output figure and the book figure, code abstract)

Delta Sigma Question

I also used it with good success.
For the examples, my results correlated with the expected values. For other modulators generated specifically for my application, the results were as expected.

Re: Delta Sigma Question

electronrancher said:

I also used it with good success.
For the examples, my results correlated with the expected values. For other modulators generated specifically for my application, the results were as expected.

Click to expand...

hi electronrancher,

what do you mean by "expected"? expected from your calculation? or expected from the book?

thanks

Added after 6 minutes:

Book: Understanding Delta-Sigma Data Converters.
In Chapter 8, High-Level Design and Simulation, I am trying to follow the instruction to simulate the 5th order low pass modulator (3-level quantizer). However, what I got are different from figures shown in the book, for example:

Figure 8.3 DSM Output Waveform: In general, my waveform is different from the one in the book. Particularly, in my simulation, all the outputs are either +2 or 0 when input > 0, and all the outputs are either -2 or 0 when input < 0; in the book, there are four outputs not following this ‘rule’ in this period.

Figure 8.4 SNR calculation and spectrum plot (rectangular window): The graph I simulated is only similar to one in the book, but not exactly the same. The SNR I got in Matlab is 86.1dB rather than 76.4dB (10dB difference!).

Figure 8.5 SNR calculation and spectrum plot (Hann window): This graph is also just similar but not exactly the same as the one in the book. The SNR value is 119.3dB which is very close to the one in the book 119.2dB.

Delta Sigma Question

hi,delsig toolbox which i'm using! are u willin to scan ur book and upload it . i just need such a book!

Delta Sigma Question

i got the same result for fig. 8.4 as you (snr=86.0835).

currentmirror2000 said:

Hi all,

i know there is a toolbox created by Richard Schreier (delsig.zip in mathwork). currently i am trying to use it, but i found the simulation i got is different from what the author did in his book (page 264, 265). i use the exactly the same code he provided but the output waveforms are different and the SNR values are also different.

is there any one tried this toolbox and really used it in your design works? is the toolbox reliable? any limitation i should pay attention?

thanks in advance and please share your experience if you have.

btw, i would like to discuss this toolbox more if anybody here is using it right now.

Click to expand...

oh, ***, just let me find this.
I meet this problem too. My result is "SNR = 86.1 dB @ OSR = 64" without window, "SNR = 85.7 dB @ OSR = 64" with window. " like the window doesn't work or the toolbox does.
I follow the book step by step, this is my code:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
clear;
clc;
close all;
%synthesizeNTF
OSR= 64;
H= synthesizeNTF(5, OSR, 1);
nLev= 3;
Nfft= 2^ 13;
tone_bin= 57;
t= [0: Nfft- 1];
u= 0.5* (nLev- 1)* sin(2* pi* tone_bin/ Nfft* t);
v= simulateDSM(u, H, nLev);
n= 1: 150;
stairs(t, u, 'g');
hold on;
stairs(t, v, 'b');
%NTF simulation, SQNR cal and spectral estimation without window
spec = fft(v)/(Nfft*(nLev-1)/2);
snr = calculateSNR(spec(1:ceil(Nfft/(2*OSR))+1),tone_bin);
NBW = 1/Nfft;
f = linspace(0,0.5,Nfft/2+1); %this may be ahead?
Sqq = 4*(evalTF(H,exp(2i*pi*f))/(nLev-1)).^2/3;
figure; %add a new figure
plot(f,dbv(spec(1:Nfft/2+1)),'b')
hold on;
plot(f,dbp(Sqq*NBW),'m','Linewidth',1);
s= sprintf('SNR= %4.1fdB @ OSR= %2.0f\n', snr, OSR);
text(0.05, -20, s);
%NTF simulation, SQNR cal and spectral estimation without window
spec = fft(v.*(hann(Nfft)'))/(Nfft*(nLev-1)/4); %convert hann(Nfft) to vector matrix
snr = calculateSNR(spec(1:ceil(Nfft/(2*OSR))+1),tone_bin);
NBW = 1.5/Nfft;
f = linspace(0,0.5,Nfft/2+1); %this may be ahead?
Sqq = 4*(evalTF(H,exp(2i*pi*f))/(nLev-1)).^2/3;
figure; %add a new figure
plot(f,dbv(spec(1:Nfft/2+1)),'b')
hold on;
plot(f,dbp(Sqq*NBW),'m','Linewidth',1);
s= sprintf('SNR= %4.1fdB @ OSR= %2.0f\n', snr, OSR);
text(0.05, -20, s);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
I use matlab r2011b for windows 64bit;
hope someone's help , 3x!!!

I have tried the matlab 2008a, the result is the same..

Re: Delta Sigma Question

fh2 said:

i got the same result for fig. 8.4 as you (snr=86.0835).

Click to expand...

Have you fixed this problem?
My problem is exactly the same as you.
hope your help!

- - - Updated - - -

electronrancher said:

I also used it with good success.
For the examples, my results correlated with the expected values. For other modulators generated specifically for my application, the results were as expected.

Click to expand...

hello!
can I know what version of matlab you used?
And , can I get your code executed for that example?
thx.

I have got the difference between the book's and my. It is the window 'hann'. When I replace the 'hann(Nfft)' with 'ds_hann(Nfft)', thes same result is got, although I don't know the reason exactly .