# trouble filtering ECG channel data **URL:** \ **Category:** Mailing List Archive (read-only)\ **Tags:** list-archive\ **Created:** [April 22, 2016, 5:49pm UTC](https://mne.discourse.group/t/trouble-filtering-ecg-channel-data/1005 "2016-04-22T17:49:40Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\ **Post date:** [April 22, 2016, 5:49pm UTC](https://mne.discourse.group/t/trouble-filtering-ecg-channel-data/1005/1 "2016-04-22T17:49:40Z")
Hello all, I have written a little script that pulls the ECG channel data out of the fif file and writes a text file to pass to QRSTool (free external software). But I have some fif files with the ECG data on channel EEG063 and some on ECG063. My script works on the channel labeled EEG063, but it fails for the ECG063. Specifically, I use raw.pick to get the channel I want. I can plot it fine, it returns type mne.io.fiff.raw.RawFIF, but when I try to filter using raw.notch\_filter, I get a weird error. See below for the relevant snippets of code and outputs. I just discovered the raw.set\_channel\_types method and wonder if that could help, but I'm having trouble getting the syntax right... (also, btw, mne.sys.info() gives me an error... so I can't tell what mne version I'm running. I did attempt git pull master origin and I'm still having the problem with raw.filter.) Thanks much in advance, Megan [mschendel at XXXX ~]$ ipython Python 3.5.1 |Anaconda 2.5.0 (64-bit)| (default, Dec 7 2015, 11:16:01) In [1]: import mne In [2]: mne.sys.info() ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\ **Post date:** [April 22, 2016, 8:24pm UTC](https://mne.discourse.group/t/trouble-filtering-ecg-channel-data/1005/2 "2016-04-22T20:24:05Z")
Hi Megan, Notch\_filter will only filter the MEG/EEG channels unless you specify some channels using picks. You could do something like: picks = mne.pick\_types(raw.info, ecg=True) raw.notch\_filter(freqs = np.arange(60, 241, 60), picks=picks ) which will then find and filter the ECG data. I think if you added that to your notch\_filter and added the picks lines for EEG and ECG in your if statement, you'd be good to go. Jon ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\ **Post date:** [April 25, 2016, 8:07pm UTC](https://mne.discourse.group/t/trouble-filtering-ecg-channel-data/1005/3 "2016-04-25T20:07:59Z")
Hi Jon! Thanks for your help! I'm a bit confused on what to do with the picks = line. I tried putting it before my if statement, and adding picks to my notch statement, but I got a different error. I also tried adding picks = line inside the if statement, before I did raw.pick\_channels, but I get the same error. It seems like using picks inside the filter might be redundant with creating a raw object with raw.pick\_channels.... ? Or I'm not using something correctly. I'd very much appreciate a little more help. Thanks again, Megan ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\ **Post date:** [April 25, 2016, 8:19pm UTC](https://mne.discourse.group/t/trouble-filtering-ecg-channel-data/1005/4 "2016-04-25T20:19:28Z")
Hi Jon/ all, It seems to work if I modify the picks line to      picks = mne.pick\_types(raw.info, meg =False, ecg = True) and then include picks in my filter statements. Thanks a bunch! Megan MEG Technician The Mind Research Network 1101 Yale Blvd. NE Albuquerque, New Mexico 87106 505-272-3304