[Eeglablist] Wrapped Phase Angle from newtimef?

Maria L. Stavrinou marial.stavrinou at gmail.com
Sat Apr 17 15:04:55 PDT 2010


2010/4/17 Maria L. Stavrinou <marial.stavrinou at gmail.com>

> Dear Zach,
> You can use unwrap to un-wrap the phase that you calculate. To check if all
> goes well, try this by having a simple sinusoid as input and check the
> result, as shown in the image I am attaching. I would recommend, to do the
> phase difference of the unwraped phase,  in radians of as they are now,
> between -pi and pi. Using the function mod you can project them into [0,
> 2pi] interval.
>
> Maria
>
> 2010/4/15 Zachary Moran <zdmoran at gmail.com>
>
>> Hi Everyone,
>>
>> I'm currently investigating the relationship between phase angle and other
>> EEG variables.  In order to get phase angle, I've been taking the angle(ITC)
>> in Matlab which gives me phase angle estimates from -pi to pi radians.
>> However, when I plot this data against time I find discontinuities at pi and
>> -pi (see attached jpeg for an example), which has become problematic in
>> using it as a predictor variable.
>>
>> Does this suggest that the phase information is "wrapped", and, if so,
>> does Matlab's "unwrap(phase_angle_data)" function seem appropriate to anyone
>> else as a means of making my phase angle data better suited as a predictor?
>> Alternatively, I had initially wanted to constrain phase to between 0 and
>> 2pi radians - does anyone have any advice for how to make this conversion?
>> Any thoughts or ideas would be very greatly appreciated.
>>
>> Many thanks!
>>
>> Zach
>>
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>
>
>
> --
> --
> Maria L. Stavrinou
> MSc. PhD.
> Postdoc Researcher
> Unit of Neurophysiology
> Department of Physiology
> School of Medicine,
> University of Patras
> Greece
> tel. lab +30 - 2610-969153
> cellular +30 -6938287930
> http://physiology.med.upatras.gr/NU/
>
> https://sites.google.com/site/marialstavrinou/
>
>


-- 
-- 
Maria L. Stavrinou
MSc. PhD.
Postdoc Researcher
Unit of Neurophysiology
Department of Physiology
School of Medicine,
University of Patras
Greece
tel. lab +30 - 2610-969153
cellular +30 -6938287930
http://physiology.med.upatras.gr/NU/

https://sites.google.com/site/marialstavrinou/
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