Koji and Haixing,
We did a tolerance analysis to specify the conner frequency for passive low-pass filtering in the AA filter of Cymac. The
link to the wiki page for the AA filter goes as follows (one can have a look at the simple schematics):
http://blue.ligo-wa.caltech.edu:8000/40m/Electronics/BNC_Whitening_AA
Basically, we want to add the following passive low-pass filter (boxed) before connecting to the instrumentation amplifier:

Suppose (i) we have 10% error in the capacitor value and (ii) we want to have common-mode rejection
error to be smaller than 0.1% at low frequencies (up to the sampling frequency 64kHz), what would be
conner frequency, or equivalently the values for the capacitor and resistor, for the low-pass filter?
Given the transfer function for this low-pass filter:

and the error propagation equation for its magnitude:

we found that the conner frequency needs to be around 640kHz in order to have
with 
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