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Dear Vladimir OK. I've just found what caused the problem. It is my method of mean value calculation. Such a mistake. The link below gives a proper method of mean calculation for phase. Just to clarify, suppose one wants to calculate the mean value of say 175 and -175 degrees. Using conventional mean value calculation it is 0, but it is 180 degrees indeed. http://en.wikipedia.org/wiki/Mean_of_circular_quantities Have a good evening :-) Amir 2009/12/5 Amir Homayoun Javadi <[log in to unmask]> > Dear Vladimir > > Thanks for your reply. Yes. I converted radian to degree for my better > understanding, and still I don't have a complete coverage of -180 and 180. > Even worth than that. It doesn't cover -90 and +90. Anything you might guess > that I've missed? > > I simply multiplied all the values to 180/pi > > Have a good weekend :-) > Amir > > > > > On 4 Dec 2009, at 22:35, Vladimir Litvak <[log in to unmask]> > wrote: > > Dear Amir, >> >> The phase is indeed in radians so the values should be between -pi and >> pi. If you average the phase using the 'vector (PLV)' option you will >> get values between 0 and 1. If I compute the phase on the tutorial >> example in SPM I get values distributed more or less uniformly between >> -3.14 and 3.14 as expected. >> >> Best, >> >> Vladimir >> >> On Fri, Dec 4, 2009 at 9:05 PM, Amir H Javadi <[log in to unmask]> >> wrote: >> >>> Hi >>> Dear Vladimir :-) >>> Another question, this time about phase in Time-Frequency analysis. I'm >>> confused with the phase analysis. I assume that the result is in Radian, >>> right? OK. I wonder why I don't have a full range of angles from +90 >>> degrees >>> to -90 degrees? In none of the channels I have 90 degrees. In some of the >>> channels the min and max are even -25' and +25'. It is almost symmetric >>> in >>> most of the channels, though. Am I missing something? How come I don't >>> have >>> for example +89 degrees? The data is for -200 ms before the stimulus >>> onset >>> to 3900 ms after the stimulus onset, with 512 samples/second. >>> Time-Frequency >>> analysis with 0.2 Hz frequency steps. No digital filter except one 1 Hz >>> High-pass filter. Frequency range from 2-40 Hz. >>> Again and again thanks for your attention. >>> Have a good evening :-) >>> Amir >>> >>> >>>