Sigma Delta ADC -SNR & SNDR calculation

hiiiiiiii

I'm working on sigma Delta ADC
CAN ANY1 PLEASE HELP ME ON WORKING WITH CADENCE SPECTRE FOR snr CALCULATION

HOW MANY CYCLES I SHOULD RUN THE TRANSIENT ANALYSIS??


IN ORDER TO CALCULATE snr
PLEASE HELP ME IN FIGURING OUT THESE VALUES...

how to come to conclusion to FFT fundamental frequency of input signal ,
NO. of samples, should give you enough noise samples to measure SNR.
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i'm goin for OSR -64
12800HZ=CLK FREQUENCY
then input freq shud be 50hz

but i'm confused by seeing some other calcualtions based on FFT SNR from other posts ...

how to come 2 conclusion abt...
Nf sample?????
No.of FFT points..????

how long to run transient analysis???
which points to be strobbed in transient analysis???

please do help..i'm confused

with regards ,
mnk...
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To calculate SNR more calculations than a simple FFT are required. So, it is easier to import the results into matlab, then calculate the SNR.
In order to transfer results to Matlab, one can write a Verilog-A module to capture the output of the modulator in right time based on modulator clock and then write the data in a file. Matlab can simply import the text files and convert to array. For SNR/SNDR calculation in Matlab, you can use delta sigma toolbox or write your own codes. Anyway, it should include following steps.
1- window the data by blackman, or hann, etc.
2- extract signal power from the data.
2-1- to do so, both sin and cosin vectors of the signal frequency should be multiplied to data, and then sum the total energy at DC.
3- calculate noise+distortion (N+D) power as: total power - signal power
4- SNDR= signal power / N+D power

May help,
Ali

Hello,

This is my first participation to this forum. Happy to be with you.

I found in some researchs formulae to calculate SNR, you find attached to this message two of them

Now the question is: If the NTF function is complicated, how to calculate its integral?

Good luck

Hi,

My comments were about transient simulations. If you need to find SNR through equations, you may replace Z (or S) with exp[jw] (or jw), where w=2*pi*f. Then sweep the f along with the bandwidth and calculate the signal and noise power.

Ali