[Eeglablist] pop_newcrossf() timefreq winsize padratio question

[fissell at pitt.edu]

Hello,

We are using pop_newcrossf() in eeglab7_1_7_18b and
trying to figure out winsize issues.
Looking at timefreq.m,
g.winsize = max(pow2(nextpow2(frame)-3),4);
g.nfreqs= g.winsize/2*g.padratio+1;
It looks like the window size is defaulting to about 1/4
the input timeframe.
What is the rationale for that ?  1/4 seems a bit big
to me.  Was that to get the desired frequency granularity ?
Is there a standard window size for eeg coherence studies ?

The number/size of the frequency bins looks like it
is set by the Nyquist limit (g.winsize/2) but then
adjusted by g.padratio that defaults to 2.

When we cut our winsize in half the number of
frequency bins was also cut in half, as per the
code I saw.  Can we just compensate for this by
doubling the padratio to get back the smaller sized
frequency bins ?    Can we do this up until the point
the bins would have the frequency width one would
have gotten by just doing an unpadded fft on the
whole frame (ie governed by the sampling rate of the
input data) ?  Or, what are the limits of adjusting padratio ?

thanks
Kate