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Design >> Analog Design >> SNR calculation
https://designers-guide.org/forum/YaBB.pl?num=1162001073

Message started by LRC on Oct 27^th, 2006, 7:04pm

Title: SNR calculation
Post by LRC on Oct 27^th, 2006, 7:04pm

Hi,

I am trying to calculate SNR of my sampling circuit by doing the following:
1. Transient sim using spectre. fin/fsample = M/N, where 2M<N, N and M are prime to each other. N is the total number of samples (eg. 256)
2. In ADE, apply calculator function dft to my transient output waveform --- dft(waveform, 2n, 514n, 256, 'rectangular')
3. Export the dft data to a file.
4. In matlab, I loaded the exported data, then
VFund=max(mag) //find the fundamental
VNoise=sqrt(sum(mag.^2)-VFund.^2) // Noise
snr = 20*log10(VFund/VNoise
NumberOfBits = (snr-1.76)/6.02

Am I correct? Did I calculate SNDR instead?
When tuning the switches of S/H circuit, what is the right way to calculate the number of bits the circuit has already achieved?

Thanks for the help.

LRC