SNR calculation of Delta Sigma ADC after Modulator and After Decimation

[Eminent.Engineer]

Hello Everyone

I have designed a decimation filter for Delta Sigma ADC and now I want to calculate the SNR of Delta Sigma ADC after the modulator and then after Decimation. As far as Schrier and Malcovati's Toolboxes are concerned I was unable to apply them (How to use them because lot of parameters to be mentioned ? :|) to decimated data so any helpful tutorial/suggestion related to problem will be highly appreciated.

Thanks to all.

 

[fasto2008]

hello Eminent.Engineer,

I hve also designed a delta sigma ADC and i calculate the SNR .In order to caculate the SNR after the modulator you must make the fast fourier transform function (FFT) by MATLAB after the modulator.

About the decimation,until now i have designed the complete ADC in Smulink (MATLAB) then by using CADENCE, i only designed the modulator with layout.
My problem is how to design this filter with layout.



regards
fasto

 

[Eminent.Engineer]

I hve also designed a delta sigma ADC and i calculate the SNR .In order to caculate the SNR after the modulator you must make the fast fourier transform function (FFT) by MATLAB after the modulator.

Thanks for your timely reply. Can you share the MATLAB code (it will be really helpful) ?

 

[fasto2008]

in this case we suppose that y is the output of modulator:

a=fft;
b=abs(a.*conj(a));
plot(10*log10(b/max(b)));
xlabel('Frequency (Khz)');
ylabel('Output spectrum (dB)');
grid;

About your decimation filter for Delta Sigma ADC, can you share me as an exemple the MATLAB code.

Thanks for help

 

[Eminent.Engineer]

About your decimation filter for Delta Sigma ADC, can you share me as an exemple the MATLAB code.

Since I am using Cascaded Integrator Comb (CIC) filter as Decimation Filter and its implementation (with brief description) is available at http://www.dsplog.com/2007/07/01/example-of-cascaded-integrator-comb-filter-in-matlab/
Hope this will be helpful.