# Frequency analysis
**URL:** https://mne.discourse.group/t/frequency-analysis/1943
**Category:** Mailing List Archive (read-only)
**Tags:** list-archive
**Created:** [August 30, 2019, 12:16am UTC](https://mne.discourse.group/t/frequency-analysis/1943 "2019-08-30T00:16:39Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@system](https://mne.discourse.group/u/system)
#### Post date: [August 30, 2019, 12:16am UTC](https://mne.discourse.group/t/frequency-analysis/1943/1 "2019-08-30T00:16:39Z")
External Email - Use Caution
Dear MNE team,
First of all, thank you for your hard work.
I am comparing different methods for EEG frequency analysis, and I have the following question/suggestions:
\* in "psd\_array\_multitaper" the user can decide to normalize the PSD by N or N\*Fs, however in "psd\_array\_welch" such choice is not available. Is this the wanted behaviour ? "psd\_array\_welch" is normalize with N\*Fs (default of scipy spectrogram I believe)
\* In "psd\_array\_welch", the type of windowing is restrained to 'hamming' windows. Would it be possible to add an argument to choose it ?
\* I am not very familiar with stockwell transform, but is it possible to get a spectrogram out of it ? I wanted to compare it with the other methods.
Cheers,
Bastien
---
### Author:  [@system](https://mne.discourse.group/u/system)
#### Post date: [August 30, 2019, 3:30pm UTC](https://mne.discourse.group/t/frequency-analysis/1943/2 "2019-08-30T15:30:22Z")
External Email - Use Caution
> - in "psd\_array\_multitaper" the user can decide to normalize the PSD
> by N or N\*Fs, however in "psd\_array\_welch" such choice is not available. Is
> this the wanted behaviour ? "psd\_array\_welch" is normalize with N\*Fs
> (default of scipy spectrogram I believe)
>
> We should probably just use the Welch-style normalization everywhere. It
should at least be the default. Feel free to open an MNE-Python GitHub
issue and we can decide how to unify these.
> - In "psd\_array\_welch", the type of windowing is restrained to
> 'hamming' windows. Would it be possible to add an argument to choose it ?
>
> Sure, feel free to make a PR to add this.
> - I am not very familiar with stockwell transform, but is it possible
> to get a spectrogram out of it ? I wanted to compare it with the other
> methods.
>
> You can get a time-frequency representation of the data from the Stockwell
transform. I am not too familiar with it either, but Its Wikipedia page
\<[https://en.wikipedia.org/wiki/S\_transform>](https://en.wikipedia.org/wiki/S_transform>); says it's a generalization of
the STFT.
Eric
-------------- next part --------------
An HTML attachment was scrubbed...
URL: [http://mail.nmr.mgh.harvard.edu/pipermail/mne\_analysis/attachments/20190830/34cb2f10/attachment.html](http://mail.nmr.mgh.harvard.edu/pipermail/mne_analysis/attachments/20190830/34cb2f10/attachment.html)