[Mne_analysis] How to filter harmonics?

[Megan Schendel]

Hi all,
     I've also been trying to figure out filtering, and getting a bit stuck
on what to do with the result of such.  If I follow along above and then do
something like:

filtered_data = raw.notch_filter(freqs=harmonics[:-1]+noise_freq//2,
notch_widths=noise_freq - 2*width)

I can't treat the result like a raw RawFIF, and if I ask python

type(filtered_data)
NoneType

So how does one use (say, plot) such a result?

Thanks!
Megan




MEG Technician
The Mind Research Network
1101 Yale Blvd. NE
Albuquerque, New Mexico 87106
505-272-3304


On Wed, Mar 23, 2016 at 10:10 AM, JR KING <jeanremi.king at gmail.com> wrote:

> Thanks!
>
> For the record I did:
>
> noise_freq = 60.  # US line noise
> width = 2. # notch widh in Hz
>
> # harmonics until nquist
> n_harm = raw.info['sfreq'] // (2. * noise_freq) + 1
>
> # band pass first to last harmonics
> harmonics = noise_freq * np.arange(1, n_harm)
> raw.filter(noise_freq - width, harmonics[-1] + width)
>
> # band stop filter in between harmonics (it's not really a notch, since
> the freq width is very large)
> raw.notch_filter(freqs=harmonics[:-1]+noise_freq//2,
> notch_widths=noise_freq - 2*width)
>
> JR
>
> On 23 March 2016 at 10:13, dgw <dgwakeman at gmail.com> wrote:
>
>> Hi JR,
>>
>> what about:
>> bandpass: 55: 245, plus notch filters for the other gaps
>>
>> d
>>
>> On Wed, Mar 23, 2016 at 10:11 AM, JR KING <jeanremi.king at gmail.com>
>> wrote:
>> > Hi all,
>> >
>> > Is there a way in MNE to do the opposite of notch-filtering so as to
>> filter
>> > out everything but the line noise and its harmonics?
>> >
>> > I'm typically trying to filter the signals so as to only keep the 60,
>> 120,
>> > 180, 240 Hz frequency bands.
>> >
>> > Thanks!
>> >
>> > JR
>> >
>> >
>> >
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