yushen_yang
Newbie level 6
Hi all,
I am design a 10bits pipeline ADC and by followingprevious articles I use Matlab to do FFT. But here are the problems I met.
fin=100Khz, fs=10Mhz,
N=8192(number of data points in FFT),
M=83 (integer number of cycles within the sampling window),
First I used coherent sampling method to do FFT and I got a result, freqd_1.
Then I used window sampling mehtod (hamming window)to do FFT again and got freqd_2.
Why are the noise floors in these two pictures different?
how should I determine the noise floor to get the SNR?
SNR=nosie floor - 10*log (fs/2/8192)? Is this right?
why are the bins quite high comparing to noise floor?
Yu-Shen
I am design a 10bits pipeline ADC and by followingprevious articles I use Matlab to do FFT. But here are the problems I met.
fin=100Khz, fs=10Mhz,
N=8192(number of data points in FFT),
M=83 (integer number of cycles within the sampling window),
First I used coherent sampling method to do FFT and I got a result, freqd_1.
Then I used window sampling mehtod (hamming window)to do FFT again and got freqd_2.
Why are the noise floors in these two pictures different?
how should I determine the noise floor to get the SNR?
SNR=nosie floor - 10*log (fs/2/8192)? Is this right?
why are the bins quite high comparing to noise floor?
Yu-Shen
