[Mne_analysis] difference between Raw.plot_psd and plot via computing psd and freq by psd_multitaper

[chanderler mei]

Thank you very much!

Ning

On Wed, Oct 5, 2016 at 6:15 PM, Eric Larson <larson.eric.d at gmail.com> wrote:

> `raw.plot_psd` uses the Welch method by chunking the signal in time,
> whereas `psd_multitaper` does not.
>
> Eric
>
>
> On Thu, Oct 6, 2016 at 2:56 AM, chanderler mei <semsociaty at gmail.com>
> wrote:
>
>> Hi all,
>>
>> I am trying to plot the power spectral density of 6 EEG channels
>> (F3,F4,C3,C4,O1,O2), but Raw.plot_psd gives me a very different plot
>> compared to plotting the freq and psd computed by psd_multitaper. Here is
>> the code:
>>
>> raw.plot_psd(tmin=0,tmax=60,fmin=0,fmax=50,area_mode='std')
>>
>>
>> f,ax=plt.subplots()
>> psds,freqs=psd_multitaper(raw,low_bias=True,tmin=0,tmax=60,b
>> andwidth=None,fmin=0,fmax=50,proj=True,picks=picks,n_jobs=1)
>>
>> psds = 10*np.log10(psds)
>> psds_mean = psds.mean(0)
>> psds_std = psds.std(0)
>>
>> ax.plot(freqs,psds_mean,color='k')
>> ax.fill_between(freqs,psds_mean - psds_std, psds_mean +
>> psds_std,color='k', alpha=.5)
>>
>> Here are the graphs:
>>
>> [image: Inline image 2][image: Inline image 1]
>>
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