how can I decide the points of blackman window?

Started by stephenduan4513 May 29, 2006
I am trying to measure the SNR of a second order sigma-delta ADC. I want
to just do a FFT analysis for the output of the quantizer. So, I collect
65536 points for FFT. I was told that I should use a Blackman window
here.But how many points of the blackman window should I use?
Here are some specs:
sample frequency:12.5MHz
Baseband frequency:20KHz
Input signal freq:1000Hz
Is there any idea how I can decide the points of that window?
Or could anyone tell me the relationship between the input freq,sampling
freq, FFT points and windows length?