Hi Eric, I think I can do that over the holiday. --David On Tue, Nov 22, 2016 at 7:00 AM, <scipy-dev-request@scipy.org> wrote:

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Today's Topics:

1. Re: signal.spectrogram doesn't change nperseg to length of window? (Eric Larson)

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Message: 1 Date: Mon, 21 Nov 2016 16:15:19 -0500 From: Eric Larson <larson.eric.d@gmail.com> To: SciPy Developers List <scipy-dev@scipy.org> Subject: Re: [SciPy-Dev] signal.spectrogram doesn't change nperseg to length of window? Message-ID: <CAGu2niVW-MWH4h9Hk+tP7dssDv9YJ6JhJrQOvei8NrRxHQoK HQ@mail.gmail.com> Content-Type: text/plain; charset="utf-8"

It looks like you are reading the docs correctly. From looking at the code, I can confirm that it doesn't change `nperseg` based on what is passed for `window`. So it looks like a bug to me.

Do you have time to look into making a Pull Request to fix it?

Eric

On Sat, Nov 19, 2016 at 10:41 PM, David Nicholson <nicholdav@gmail.com> wrote:

...

Hi scipy-dev list,

I'm using spectrogram from scipy.signal with a custom window. My understanding from the docs is that when I provide an array_like for the window, the value for nperseg will change from the default of 256 to whatever the length is of the window I provide.

But instead I get an error saying 'noverlap must be less than nperseg' and when I check with pdb I can see that nperseg is still the default value. I'm using a value for noverlap that's larger than the default nperseg, but less than the length of the window. I don't get the error if I call the function with 'nperseg=window.shape[0]'.

I skimmed the source and don't see anything in the _spect_helper function that would change nperseg to the length of window.

Am I misunderstanding the docs, or am I calling the function wrong, or is this a bug?

Here's my code: from scipy.io import wavfile from scipy.signal import slepian # i.e. 'DPSS' window used for FFT from scipy.signal import spectrogram

FFT_SIZE = 512 FFT_OVERLAP = FFT_SIZE - 32 win_dpss = slepian(FFT_SIZE, 4/FFT_SIZE) #shape =

[rate,data] = wavfile.read('a_file_you_have.wav') f,t,spec = spectrogram(data, rate, window=win_dpss, noverlap=FFT_OVERLAP)

Thanks for your help --David

-- David Nicholson, Ph.D. Candidate Sober Lab <http://www.biology.emory.edu/research/Sober/Home.html>, Emory Neuroscience Program. <http://www.emory.edu/NEUROSCIENCE/> www.nicholdav.info; <http://www.nicholdav.info> https://github.com/NickleDave

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