# MATLAB code for PSD plot and SNR of Sigma Delta Modulators

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#### gsuarez

##### Junior Member level 1 power spectral density matlab

Here is a simple but good MATLAB code to obtain the Power Spectral Density (PSD) plot of Sigma Delta Modulators. It also computes de Signal-to-Noise Ratio (SNR) in dB. An example data is included with instructions on how to use it. Any questions please let me know.

George

#### nahid.fatahi

##### Newbie level 1 sigma delta modulator matlab

gsuarez said:
Here is a simple but good MATLAB code to obtain the Power Spectral Density (PSD) plot of Sigma Delta Modulators. It also computes de Signal-to-Noise Ratio (SNR) in dB. An example data is included with instructions on how to use it. Any questions please let me know.

George

hi George

how to simulate a third order delta sigma modulator for fractional N frequency synthesizer to reduce fractioal spurs?

nahid

• yavar133 and ofalcin

Points: 2

### yavar133

Points: 2

#### king87

##### Newbie level 1 hi gsuarez,

Great code! It's exactly what I was looking for.

However, I'm getting an error while simulating it. Here's the command I'm using to simulate this,

frequency_plot(sc_out, 2.56e6, 1, 4, 1, 10000,1,1,3,0)

and here's the error,

??? Attempted to access temp(0); index must be a positive integer or logical.

Error in ==> snrflx_v2 at 117
f1=temp(templ)-1;

Error in ==> frequency_plot at 42
[snrdb,fundf,fout,xfout]=snrflx_v2(xt1,fs,tn,bin,f1,f2,win,dc);

#### jagan2

##### Newbie level 2 Same problem here..

• gushenzwt

### gushenzwt

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#### wonbef

##### Full Member level 3 thanks! it is a bit useful!

#### tanxiaoliang

##### Newbie level 1 #### zabtorres

##### Newbie level 1 Re: power spectral density matlab

wat do u mean by multiple of base 2? is it a bit stream? sorry for askin this

#### pankaj jha

##### Full Member level 3 Re: power spectral density matlab

Here is a simple but good MATLAB code to obtain the Power Spectral Density (PSD) plot of Sigma Delta Modulators. It also computes de Signal-to-Noise Ratio (SNR) in dB. An example data is included with instructions on how to use it. Any questions please let me know.

George

Dear George'
Thanks for uploading the code. but I think this code is suitable only for real sigma delta modulators.
I need a MATLAB code to plot the PSD for a quadrature sigma delta modulator. Can u provide the same to me???

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