Tech Note 283 Detail

Anti-aliasing?

Affected Products:

CI-6400 ScienceWorkshop 500 Interface

Problem/Symptom:
Does the SW500 interface have anti-aliasing?

PASCO Solution:
The ScienceWorkshop 500 interface will only oversample 8 X for frequencies below 100 Hz and 1 X for higher software-set sampling rates, but for maximum precision you want to average n samples such that you are constantly measuring, increasing the precision by a factor of n. The ScienceWorkshop interface does not have any anti-aliasing filters, so there is some folding of frequencies beyond the Nyquist limit of 20 kHz into the signal. This is noticeable above 1 kHz, going to 1/10 of the signal value for 2 kHz. One way of decreasing the effect of aliasing is to place a passive filter on the input.

Creation Date: 10/24/2001
Last Modified: 04/11/2003
Mod Summary: