Delta Sigma Toolbox

High-level design and simulation of delta-sigma modulators

Description

The Delta-Sigma Toolbox includes nearly 100 functions which support NTF synthesis, modulator simulation (from an NTF or a structure), realization, dynamic range scaling, SNR estimation and more. The toolbox is well-documented via the accompanying DSToolbox.pdf manual.

For further information regarding the Toolbox and Delta-Sigma modulators in general consider purchasing "Understanding Delta-Sigma Data Converters" by Schreier and Temes (ISBN 0-471-46585-2).

Acknowledgements

This file inspired Data Weighted Averaging For Simulink, Delta Sigma Converter Spurious Tone Predictor, and Frequency Domain Min Max Optimization For Delta Sigma Modulators.

• Required Products: Control System Toolbox; Signal Processing Toolbox
• MATLAB release: MATLAB 7 (R14)
• Other requirements: Users should compile the simulateDSM.c and simulateESL.c files to speed up simulations.

[ding]

Dear Richard Schreier,
I am a new man in deltasigma, so I follow your book" Understanding Delta-Sigma Data Converters by Schreier and Temes (ISBN 0-471-46585-2)" step by step, and I meet a problem "figure 8.4" and "figure 8.5" in page "265" and "266".
In your book, the SNR without window is "SNR = 76.4 dB @ OSR = 64",the SNR with window is "SNR = 119.2 dB @ OSR = 64".
But to my simulation, the result is "SNR = 86.1 dB @ OSR = 64" without window, "SNR = 85.7 dB @ OSR = 64" with window.
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(n), u(n), 'g');
hold on;
stairs(t(n), v(n), '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;

[pankaj jha]

I am trying to implement a SDM using delsig toolbox. The following are the commands I try to run, along with the errors.

H = synthesizeChebyshevNTF(2,12.5,1,1.5,0);
>> stf = zpk([],[],1,1) ;
>> [a g b c] = realizeNTF(H,'CRFFD',stf)
Error using /
Matrix dimensions must agree.

Error in realizeNTF (line 246)
a = -real(zL1/T);

Can you suggest me how to rectify the error???

[Maxim]

Possible bug in function quantize() (file simulateDSM.c).
In saturate code:
if( vv > nLevels )
vv = nLevels-1;
else if( vv < -nLevels )
vv = 1-nLevels;

May be correctly:

if( vv > (nLevels -1))
vv = nLevels-1;
else if( vv < (1-nLevels) )
vv = 1-nLevels;

Regards,
Maxim

[macau]

good thanks

[Zhao Li]

To the folks having trouble compiling the Mex files on Windows with 64-bit Matlab (bizet74 perhaps?), you will need to define the '__STDC__' symbol. For example, to compile simulateDSM.c, you would do 'mex -D__STDC__
simulateDSM.c'

Regards,

Zhao

[pankaj jha]

Respected Sir,

I am trying to simulate a sixth order sigma delta modulator using the
"Delta Sigma Toolbox".

1) My desired NTF is a 6th order Chebyshev type II high pass filter.
Hence, I ran the following command :
>> ntf = synthesizeChebyshevNTF(6,64,2,1.5,0)

The toolbox outputs the function given below:
Zero/pole/gain:
(z^2 - 2z + 1) (z^2 - 1.999z + 1) (z^2 - 1.998z + 1)
-----------------------------------------------------------------------
(z^2 - 1.629z + 0.6655) (z^2 - 1.705z + 0.7437) (z^2 - 1.854z + 0.8979)

Sampling time: 1

2) I wish to implement the above NTF using the "CIFB" structure. So
I ran the following command:
>>[a,g,b,c] = realizeNTF(ntf,'CIFB')
which gives the output
a =

0.0001 0.0013 0.0124 0.0794 0.3223 0.8120

g =

0.0002 0.0022 0.0012

b =

0.0001 0.0013 0.0124 0.0794 0.3223 0.8120 1.0000

c =

1 1 1 1 1 1

3) I tried to construct the "CIFB" structure using the coefficient
values provided by the toolbox, mentioned in the previous step.

4) I try to analyse the frequency content of the output (y2 in the
simulink file attached with this mail). I ran the following commands :
>> NFFT = 2^nextpow2(length(y2)); % Next power of 2 from length of y
>> Y = fft(y2,NFFT)/length(y2);
>> f = 300e6/2*linspace(0,1,NFFT/2+1);
>> plot(f,2*abs(Y(1:NFFT/2+1)))

5) The output is more like a low pass filter and not a high pass expected.

Hence, i request you to kindly have look at the .mdl file and the
commands executed by me, and help me find the mistake that I have
committed.

[Mike Woodward]

If you're interested in this submission, you might also like the new, free mixed-signal library available from here: http://www.mathworks.com/programs/mixed-signal/index.html

[Kevin]

 

[Irfan Chaudhry]

 

[zhang fuquan]

good job

[nont none]

hi.how can i download dsp toolbox?

[Mohammad alhawari]

@ bizet74
did u find how to solve ur problem coz am facing the same problem???

[Sridhar]

Dear Dr. Schreier I am trying to use the toolbox to simulate a Sigma Delta Converter in Simulink. I was able to do it succesfully for a CIFF structure and now I am doing it for a CIFB structure.
Although I am able to simulate the Sigma Delta with the toolbox, it is unstable in Simulink.
Moreover I find that the CIFB topology shown in the manual is different as in this report (refer to figure 4 on page 5):
http://www.terasoft.com.tw/events/conference/2006/cfp/2006CFP_selected_Papers/3/3-2.pdf

My code is:
order=4;
OSR=545;
OPT=1;
H_inf=1.2;
ntf=synthesizeNTF(order, OSR, OPT, H_inf, f0);
[a,g,b,c]=realizeNTF(ntf, 'CIFB');
ABCD = stuffABCD(a,g,b,c,'CIFB');

Then I use the calculated a,g,b,c values in simulink.

best regards and thanks

Sridhar

[bizet74]

Thanks for you answer but unfortunately this is what I usually do.
I have copied the toolbox in a directory (say c:\delsig) and I set this directory as the current Matlab directory and then I typed, for instance, mex simulateDSM.c and I obtained the afore mentioned errors.

[ASH VLSI]

@ bizet74
hi friend
i faced same problem .... it can be solved by setting toolbox directory as matlab current directory and then giving the command

[bizet74]

Hi!

I have some problems trying to compile simulateDSM.c, flattenStruct.c, and simulateESL.c. A part from several warnings I obtain these errors

simulateDSM.c(363) : error C2371: 'mexFunction' : redefinition; different basic types
C:\PROGRA~2\MATLAB\R2010A\extern\include\mex.h(147) : see declaration of 'mexFunction'

flattenStruct.c(27) : error C2371: 'mexFunction' : redefinition; different basic types
C:\PROGRA~2\MATLAB\R2010A\extern\include\mex.h(147) : see declaration of 'mexFunction'

simulateESL.c(547) : error C2371: 'mexFunction' : redefinition; different basic types
C:\PROGRA~2\MATLAB\R2010A\extern\include\mex.h(147) : see declaration of 'mexFunction'

I'm working with MATLAB Version 7.10.0.499 (R2010a) and Microsoft Visual C++ 2008 Express.

Does any one can help me?

Thank a lot in advance.

[ASH VLSI]

can i model non idealities using this tool box ..........is it possible ????

[ASH VLSI]

may i know how to use this tool box please .with some simple examples ...can anybody share it on my email :[e-mail]

[yang shisong]

I want to know how to use the toolbox,can you share me some example?thanks. my email:[e-mail]

[he shiqing]

I got it.It's free to download ! I am sorry for misundstaning it

[he shiqing]

how to buy the Delta Sigma Toolbox ????

[shaohuip ?]

Thanks very much for your sharing. For quadrature band pass sigma-delta ADC design, when we use the synthesizeQNTF to get the NTF, then we can get the ABCD matrix by the realizeQNTF function. Finally how we can determine the coefficient like the [a,g,b,c] in low pass or band pass structure? Also for the quadrature structure, there is FF/FB/PFF/PFB, what is the difference between them and the previous CIFF/CIFB/CRFF/CRFB?
Thanks very much.

[Thierry Tambe]

Outstanding Work. Exceptionally helpful in the simulations of SNDR versus DAC jitter, thermal noise and THD.

[Vishal Saxena]

The delta-sigma toolbox by Dr Schreier is a mandatory tool for anyone serious about delta-sigma ADC design. The CT DSM extensions in the 2009 version look very useful and we will be evaluating them in a delta-sigma converter design course being taught at Boise State.
http://cmosedu.com/vsaxena/courses/ece697/s10/ECE697.htm

[Praveen Kumar]

Can I access the older versions of this toolbox. I am particularly interested in the old documentation.

[zhang]

Who can tell me, in the book "Understanding Delta-Sigma Data Converters ", in page 265,

1. spec = fft(v)/(Nfft*(nLev-1)/2),
why (nLev-1)/2 should be counted in to the spectrum computation?

2. Sqq = 4 * (evalTF(H,exp(2*pi*f))/(nLev-1)).^2/3,
why does 4/3 mean in this equation?

Thanks a lot!

[Payam]

Dear Richard,

First of all many thanks for developing such a nice toolbox and authoring such a great book "Understanding Delta-Sigma Data Converters".
I am about to design a 4th order/10MHz BW/CT/Quadrature delta-sigma ADC.
Unfortunately, I couldn't find any function and demo regarding design and simulation of a complex filter in the delsig toolbox. I would be grateful if you inform me about any enhancement of this toolbox for designing complex DS ADCs.
Your time and consideration are appreciated in advance.

[Aztec Wei-Ting]

When I download this toolbox and run synthesizeNTF.m, an error always comes out at line 209 and column 22. Does any method to solve this problem? Thank you very much!

[Ras123 V]

 

[Quan]

it's my mistake. it's the total power in the signal bins to the total power in the noise bin.

[Quan]

Thanks for such a useful tool box. I have a question of SNR calculation.
In the tool box, the function, caltulateSNR,is used to approximate in-band signal power and noise power, and then SNR is calculated. the codes are as follows:
signalBins = [f-nsig+1:f+nsig+1];
signalBins = signalBins(signalBins>0);
signalBins = signalBins(signalBins<=length(hwfft));
s = norm(hwfft(signalBins)); % *4/(N*sqrt(3)) for true rms value;
noiseBins = 1:length(hwfft);
noiseBins(signalBins) = [];
n = norm(hwfft(noiseBins));
if n==0
snr = Inf;
else
snr = dbv(s/n);
end

My question is: Since the length of signal bins and noise bins are totally different, how can signal power and noise power be substituted by
s = norm(hwfft(signalBins)) and n = norm(hwfft(noiseBins)), respectively.
I think the signal power and noise power should be like s = norm(hwfft(signalBins))*(4/N*sqrt(length(signalBins))) and n = norm(hwfft(noiseBins))*(4/N*sqrt(length(noiseBins))), respectively.
May be I'm wrong. But i'm really confused.

[sandy sandy]

After u download how to u run the files.always error is occuring

[lu yan]

I doenloaded this toolbox,but now I have a question.when i run synthesizeNTF.m,an error always comes out in 209 line.Browsing a lots of forum ,I find that the question is very popular.I expect you give a way to the problem,thank you from my heart!looking forword to your letter!

[Lars Sundström]

A significant contribution to the mixed-signal community around the world.

[Xu YanFeng]

very good

[Liu qiuliang]

very good!

[shifei hu]

very useful?Thanks Very much!!

[zhang dongqing]

 

[zhang dongqing]

It is very useful for the filter design, thanks

[Aren aren00]

Very good!

[Mareers Samuel]

Thanks for useful toolbox.Is it compatible with
matlab clones liek Scilab n Octave.If not wat are the modifications required??

[di li]

Thank you very much!!!

[swathi y]

 

[Xiaodong Guo]

 

[Sha Xia]

 

[shi huan dong]

excellent

[preeti chauhan]

 

[Yi WANG]

The matlab code is:

OSR=128; %over sampling rate

order =2; %the order of SDM

ntf0=synthesizeNTF(order,OSR,1); %create the optimized ntf.
stf0=ntf0; %copy the ntf to stf, so that they will have the same poles.
stf0.z=[]; %set the numerator of stf to 1.

form='CIFF';
[a,g,b,c]=realizeNTF(ntf0,form,stf0);

[Yi WANG]

I have a problem of using function "realizeNTF", if I set the "stf" has the same poles as "ntf" and use it as the input for the fucntion. Matlab tell me that:
??? Error using ==> mrdivide
Matrix dimensions must agree.

Error in ==> realizeNTF at 327
b = real(x/A);

Error in ==> Test_7755_NTF_Cap2 at 10
[a,g,b,c]=realizeNTF(ntf0,form,stf0);

[Senthil raja]

If zpk is properly modified, this software should be user friendly.

[Senthil raja]

If zpk is properly modified, this software should be user friendly.

[Ramesh Singh]

 

[HUA Siliang]

Thank you for your toolbox. I am reading your book.

[Luiz Carlos]

 

[Jhoule Houke]

Thank you very much.

[Sushi Taro]

I like sushi very much.

[Shimon Dahan]

Need more examples for designing SD structure include it's coefficients.

[mopaditis Aeolus]

 

[Jitendra Das]

 

[melika roknsharifi]

Dear Richard Schreier
Thanks for your exellent book on delta sigma and this complete toolbox

[Doreen wang]

First,I use this tool to get the coefficients of a fifthe-order sigma delta modulater.And then I made a model in simulink with these coefficients.Then filter the modulated signal with a lowpass analog filter,I could not get the original signal.I found that the third order coefficients can get the perfect results in simulink.why?Thanks.

[Steven Lin]

 

[Song-Bok Kim]

Dear Richard Schreier. Thank you for your dela sigma toolbox. I want to know if by your toolbox it is possible to simulate Continuous-time quadrature bandpass sigma-delta modulator. And if possible, please tell me how to use. Next,I kow how to simulate the feedforward summing topology without input feedforward with which feed only first stage integrator.
I look forward your reply this week.

[Song-Bok Kim]

I don't know yet how to use the Delta Sigma Toolbox. Firstly, I want to inform how to use
in Matlab simulink

[Bingxin Li]

 

[Wayne Huang]

Good! helpful.

[mehrdad yadollahi]

it's good

[mehrdad yadollahi]

fair

[Oscar Gaete]

Dear Richard,
thank you for your toolbox. It looks very impresive.
I have one questions:
if I sample 1 second audio with 8000 Khz I will get a variable with 8000 points(i.e. >>x=wavrecord(8000,8000);)
when I simulate the output of a delta sigma modulator (when the input is x) with OSR=64 the output signal has a length of 8000. Why is that?...shouldn't it be 512000 because of the oversampling?)
Thank you.

[noha zaki]

I have a simply question,like Jacob, how to initialize this toolbox in matlab?What steps should I take to use Sigma Delta modulator?I only need to give as an input some signal (ex.sinus)and observe an output as a spectrum...Thanks for answer

[xin xn]

sigma-delta box

[Jacob J]

I have a simply question, maybe somebody will be laughing:), but how to initialize this toolbox in matlab?What steps should I take to use Sigma Delta modulator?I only need to give as an input some signal (ex.sinus)and observe an output as a spectrum...Thanks for answer

[mehmet ozcelik]

gaziantep university

[Marshnil Dave]

I am trying to simulate a basic Boser and Wooley Sigma Delta modulator
in matlab. The SNR calculated using calculateSNR function of SDMtoolbox
doesn't give proper results and as STF of this B&W architecture is not
unity I am unable to simulate it using simulateSDM function of SDM
toolbox. I request you to guide me simulating second order B&W SDM in
matlab and predicting the SNR correctly.

[Marshnil Dave]

I am trying to simulate a basic Boser and Wooley Sigma Delta modulator
in matlab. The SNR calculated using calculateSNR function of SDMtoolbox
doesn't give proper results and as STF of this B&W architecture is not
unity I am unable to simulate it using simulateSDM function of SDM
toolbox. I request you to guide me simulating second order B&W SDM in
matlab and predicting the SNR correctly.

[David Kiriev]

RE: current mirror

Don't copy everything from the book. He was a professor at Oregon State U. when he created the toolbox -- Professors don't test their codes, the graduate students do.

He just took whatever results or claims that his student gave to him...You have to try testing every code by yourself since you're not a professor :)

David Kiriev

[current mirror]

seems i do not get the same simulation results and SNR value as the book written by the author (page 264, 265); anyone got the same problem?

[jason Fong]

so smart one

[jeffrey zhu]

excellent toolbox for sdm design, realizeNTF function for CIFF topology seems not correct though.

[Mucahit Kozak]

Excellent toolbox. Essential for the design of sigma delta modulators.

[Zejian cai]

>> H=clans(5,32,5,0.95,1)
??? Error: File: D:\st\delsig\clans6.m Line: 35 Column: 37
"identifier" expected, "(" found.

Error in ==> D:\st\delsig\clans.m
On line 19 ==> NTF=clans6(order,OSR,Q,rmax,opt);

I just do it as document says. what's wrong?

[Zejian cai]

always error as following when run dsdemo6.m, who can tell me why? please
??? Undefined function or variable 'firpm'.

Error in ==> D:\st\delsig\designHBF.m (designF1)
On line 119 ==> h = firpm(2*n1-1,[0 4*fp1 1 1],[1 1 0 0]);

Error in ==> D:\st\delsig\designHBF.m
On line 42 ==> [f1 zetap phi] = designF1( delta, fp1 );

Error in ==> D:\st\delsig\dsdemo6.m
On line 19 ==> [f1,f2,info]=designHBF(fp,delta,1);

[Leon hong]

Can I use this toolbox to simulate digital D-S modulators in DAC?

[manu suryavansh]

i am not able to download

[z.z. dong]

The file firpm.m is missed when i run designHBF.m program in the matlab 6.5 R13 software. please give some suggestions if possible

[C. HO]

The calculateSNR.m is a good approximation, but might have problem when the number of points considered increased.

[C. HO.]

Organization can be improved further.

[Acuti Yang]

 

[M. Praveen]

its good

[ken vin kuo]

no

[OLL Tsai]

good!

[Mehdi Banihashemi]

 

[Naughty Boy]

Very good. But just failed to compile the simulateDSM.c under Linux Matlab 6.5, always says that the file is not normal or not existed. For Window Matlab, it is okay.

[Fakhs Huss]

 

[kareem abdallah]

 

[Mohammad Yavari]

Very useful tool to design high order single loop SD modulators
It will be nice if this toolbox is added in the next versions of MATLAB.

[Lin Chuck]

I need the synthesizeNTF and CLAN original document

[Sumant Bapat]

Nice tool. Makes life of novice delta sigma designer easy

[guillaume de cremoux]

Very good when modulator order greater than 3; otherwise the famous "0.5" coefficients do the same job. When very low OSR (<32), filter refinement does not flatten enough the NTF. Excellent tool at medium OSR, and high modulator order.

[Esmaeil Najafiaghdam]

 

[Mark Brunner]

It does what it should... thanks.

[Gary Mai]

Excellent Work. It will be great help to design sigma-delta modulator, especially in system level.

[Leo Montreuil]

Great tools for design Delta-Sigma modulator

[Paul Muller]

Very useful, not only for understanding, but also for system-level simulation for IC design

[Anas Hamoui]

Great work ... thank you.

[June sh]

It's a well done work!
Thank u!