[Eeglablist] newtimef freqs output

Thu Aug 2 17:29:49 PDT 2012

Dear Makoto,

I double checked it and the results are identical for both using 'padratio'
4 and 'nfreqs' 47. I use log-spaced frequencies, so both settings lead to
the same 47 log-spaced frequencies from 4 to 50 Hz (and all the other input
settings stay the same).

[ersp,itc,powbase,times,freqs] = newtimef(EEG.data (83,:,:), 350, [-400
996], 250, [1 0.5],'baseline',[NaN],'freqs', [4 50], 'freqscale', 'log',
'padratio', 4);

[ersp1,itc1,powbase1,times1,freqs1] = newtimef(EEG.data (83,:,:), 350,
[-400 996], 250, [1 0.5],'baseline',[NaN],'freqs', [4 50], 'nfreqs', 47,
'freqscale', 'log');

Changing the padratio to 2 and 8 changes the frequency resolution (and that
is what it should do, right?).
Using a padratio of 2 results in 23 log-spaced frequencies and a padratio
of 8 results in 94 log-spaced frequencies.

Thanks a lot, Katharina

On 3 August 2012 11:56, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:

> Dear Katharina,
>
> > I tried using 'nfreqs' 47 instead of 'padratio' 4 as you suggested. The
> > results are identical.
>
> I'm not sure if this could be true. Could you check it again?
> Also, please try 'padratio', 2 and 8 to see if it changes results.
>
> > Why is it better to define the number of frequencies
> > than to use the padratio?
>
> I misunderstood you. I thought you were saying you want to obtain
> linear scale from 4 to 50 Hz with 1 Hz interval. Please forget it.
>
> Makoto
>
> 2012/8/2 Katharina Limbach <klim366 at aucklanduni.ac.nz>:
> > Dear Makoto,
> >
> > thanks a lot for your response.
> > I think I figured out, that I was making a really stupid mistake. I
> thought
> > that the output parameters were optional and that their order did not
> matter
> > (I used [ersp,times,freqs]) . So the output that was given for 'freqs'
> was
> > actually the 'powbase' output (and likewise the 'times' output was the
> > itc...).
> >
> > So I changed my code to:
> >
> > [ersp,itc,powbase,times,freqs] = newtimef(EEG.data (83,:,:), 350, [-400
> > 996], 250, [1 0.5],'baseline',[NaN],'freqs', [4 50], 'freqscale', 'log',
> > 'padratio', 4);
> >
> > and I am now getting more sensible results (times from -260 to 860 and
> > frequencies from 4 to 50).
> > I am really sorry for this!
> >
> > I tried using 'nfreqs' 47 instead of 'padratio' 4 as you suggested. The
> > results are identical. Why is it better to define the number of
> frequencies
> > than to use the padratio?
> >
> > I have one more question about the powbase. I do not want to baseline my
> > wavelets (and I set 'baseline' [NaN]), but I am getting a powbase output.
> > Does that mean that the baseline power is computed but not used for the
> > wavelets?
> >
> > Thanks a lot, Katharina
> >
> >
> >
> > On 3 August 2012 08:06, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:
> >>
> >> Dear Katharina,
> >>
> >> Sorry for slow response.
> >>
> >> > The values range from 1.6608914e+04 to 3.0225791e+05.
> >>
> >> This means your frequency range is between 1.6 MHz to 30.2 MHz, which
> >> is like an old generation CPU clock speed. Something is seriously
> >> wrong. However, I don't know what causes this from your code.
> >>
> >> By the way, if you want something close to 4,5,6,... 50, you should
> >> use 'nfreq', 47 instead of 'padratio', 4. Could you try it to see what
> >> happens?
> >>
> >> Makoto
> >>
> >> 2012/7/22 Katharina Limbach <klim366 at aucklanduni.ac.nz>:
> >> > Dear all,
> >> >
> >> > I have a question regarding the output of the newtimef function.
> >> > I am using the following command (input data: 1 participant, 1
> >> > condition,
> >> > electrode # 67. My sampling rate is 250 Hz and the epochs go from -400
> >> > to
> >> > 996 ms (350 frames)):
> >> >
> >> > [ersp,times,freqs] = newtimef(EEG.data (67,:,:), 350, [-400 996], 250,
> >> > [1
> >> > 0.5],'baseline',[NaN], 'freqs', [4 50], 'freqscale', 'log',
> 'padratio',
> >> > 4,
> >> > 'plotphase', 'off', 'plotitc', 'off');
> >> >
> >> > The resulting plot is showing frequencies from 4 to 50 Hz (which is
> what
> >> > I
> >> > was looking for) but I do not understand the output I get for 'freqs':
> >> > The values range from 1.6608914e+04 to 3.0225791e+05.
> >> > Shouldn't they simply be in Hz and go from 4 to 50 Hz? Do I have to
> >> > convert
> >> > them to get the correct values or is there something else that I am
> >> > doing
> >> > wrong?
> >> >
> >> > Also my 'times' output is not a vector of output times in ms, but a
>  47
> >> > x
> >> > 200 martix with complex numbers.
> >> >
> >> >
> >> > Thanks a lot for your help,
> >> > Katharina
> >> >
> >> > --
> >> > Katharina Limbach
> >> > PhD Candidate
> >> > Department of Psychology
> >> > University of Auckland
> >> > Private Bag 92019
> >> > Auckland
> >> > New Zealand
> >> > tel: + 64 9 3737 599 ext 85969
> >> >
> >> >
> >> > _______________________________________________
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> >>
> >>
> >>
> >> --
> >> Makoto Miyakoshi
> >> JSPS Postdoctral Fellow for Research Abroad
> >> Swartz Center for Computational Neuroscience
> >> Institute for Neural Computation, University of California San Diego
>
>
>
> --
> Makoto Miyakoshi
> JSPS Postdoctral Fellow for Research Abroad
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>

-- 
Katharina Limbach
PhD Candidate
Department of Psychology
University of Auckland
Private Bag 92019
Auckland
New Zealand
tel: + 64 9 3737 599 ext 85969
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