If anyone understands how to pick scales for cwt using FFT I would so appreciate the advice. I am using Torrence and Compo's code that has been adapted (below). However, all I know is how to find out using scal2frq the scale/frequency relationship. Here they are talking about fourier periods and talking about picking scales based on milliseconds which I am finding very confusing. I have EEG data, sampled at 256 Hz, length(n)=315 and I am interested in looking at the cross coherence between 4 and 15 hz. Thank you to anyone who can shed light on this!! Kim
Wavelet coherence % % USAGE: [Rsq,period,scale,coi,sig95]=wtc(x,y,[,settings]) % % % Settings: Pad: pad the time series with zeros? % . Dj: Octaves per scale (default: '1/12') % . S0: Minimum scale % . J1: Total number of scales % . Mother: Mother wavelet (default 'morlet') % . MaxScale: An easier way of specifying J1 % . MakeFigure: Make a figure or simply return the output. % . BlackandWhite: Create black and white figures % . AR1: the ar1 coefficients of the series % . (default='auto' using a naive ar1 estimator. See ar1nv.m) % . MonteCarloCount: Number of surrogate data sets in the significance calculation. (default=300) % . ArrowDensity (default: [30 30]) % . ArrowSize (default: 1) % . ArrowHeadSize (default: 1) % % Settings can also be specified using abbreviations. e.g. ms=MaxScale. % For detailed help on some parameters type help wavelet. % % Example: % t=1:200; % wtc(sin(t),sin(t.*cos(t*.01)),'ms',16) % % Phase arrows indicate the relative phase relationship between the series % (pointing right: in-phase; left: anti-phase; down: series1 leading % series2 by 90°) % % Please acknowledge the use of this software in any publications: % "Crosswavelet and wavelet coherence software were provided by % A. Grinsted." %
