[Homer-users] Low pass filter error

[Grace Giles]

Good afternoon,

I am using NIRS data obtained from the Biopac fNIRS system and when I
attempt to enter filters in HomER (i.e. 0.00 high pass and 0.5, 1 or 2 low
pass) I get the error message "Filter parameters exceed Nyquist frequency."

Biopac's sampling frequency is set at 2 Hz, which I believe according to
Nyquist's Theorem means that I can only look at signals as fast as 1 Hz,
but I am not sure why a filter of 1 is a violation.

Has anyone else using Biopac come across this issue? Any insight would be
greatly appreciated. I am using HomER to analyze my data for the first
time, so still fairly new.

Best,
-- 
Grace Giles
PhD Candidate
Nutrition and Behavior Lab
Department of Psychology
Tufts University
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