[Mne_analysis] Badly resample signal

[Phillip Alday]

        External Email - Use Caution        

This is expected behavior for resampling. With resampling, you lose
temporal resolution, so fast, high amplitude deviations are lost.  This
is what happens at the beginning of your signal. Later in the signal you
see that the slower change in the mean of the signal is preserved, but
the bumps are list.

Intuitively: you have fewer samples, so you can't capture both the
deviations up and the deviations down, so they average out and you get
just the mean. So the big peak and big trough early in your example just
cancel out when resampled.

Phillip

On 22/08/2019 07:01, RODNEY PETRUS BALANDONG wrote:
>
>         External Email - Use Caution        
>
> Dear All,
>
>  
>
> The issue is about sample badly approximated
>
>  
>
> Given an original signal sampled at 100Hz, the objective was to
> downsampled it into 50 Hz
>
> The downsampling process was realised using the MNE resample.
>
>  
>
> However, as can be noticed from the image below, the sample is badly
> approximated. Instead of registering the original signal magnitude,
> the function RESAMPLE return an approximated signal magnitude.
>
>  
>
> This rise two question
>
>  1. Is it common for such badly resample to occur?
>  2. If yes, how to minimize this
>
>  
>
> The problem can be reproduced using the notebook which is accessible
> through this link
> <https://github.com/balandongiv/EyeCloseOpen/blob/master/HelpImportDownsample_EDF.ipynb>.
>
>  
>
> Thanks in advance for entertaining this request
>
>  
>
>  
>
> A close up of a map Description automatically generated
>
>  
>
>  
>
> Regards
>
> Rodney
>
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