I have a very basic question.
I am trying to use a butterworth filter but the instructions make no sense. Matlab on accepts a frequency between 0 and 1. The specific instructions say:
"The cutoff frequency Wn must be 0.0 < Wn < 1.0, with 1.0 corresponding to half the sample rate."
Lets say my data was sampled at 2500 Hz. I want to low pass filter at 20 Hz. What exactly would I need to enter for Wn and how can I figure it out on my own.
Thanks in advance!