AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

History of AFNI updates  

|
August 29, 2003 12:02PM
Hi,
I'm trying to band pass filter using 3dFourier twice.

My block is 20s long and my TR=2s, so I figure I should keep everything between :
1/40s (being conservative) to 1/4s (nyquist)
so I do:

3dFourier -lowpass 0.25 -prefix 06_lp mydata+orig

3dFourier -highpass 0.025 -prefix 06_bp 06_lp+orig

looking at 06_lp, it's all 0's. But the high pass filtered version of 06_lp (06_bp) is not all 0's. This doesn't make sense. Am I doing something wrong?


thanks,
George
Subject Author Posted

bp filtering

George Tourtellot August 29, 2003 12:02PM