Filter_length warning

[BarryLiu97 (Barry Liu)]

Hi, When I used epoch.filter(1, 100), I’ve got this warning:

How do I change the filter length?

[agramfort (Alexandre Gramfort)]

you cannot apply a reliable high pass with very short epochs

A

[BarryLiu97 (Barry Liu)]

Thanks! I just found that!

[richard (Richard Höchenberger)]

What you should do instead is filter the raw data.

Or if you need to filter on the epochs level, make the epochs longer, filter, and crop them to you desired duration.