[FieldTrip] time-frequency analysis: temporal alignment of output

Aaron Schurger aaron.schurger at gmail.com
Fri Feb 7 12:43:04 CET 2014

I am running a time-frequency analysis using ft_freqanalysis with the
wavelet method. I assume that the output in each frequency band is
temporally aligned to the midpoint of the wavelet (thinking in terms
of convolution): i.e. the power value that I get at time 0.300, for a
given frequency f, is precisely the dot product of f's wavelet
CENTERED at 0.300 sec in the data. Is that correct? If so, how can I
ask for the output of freqanalysis to be time aligned to the leading
edge of the wavelet rather than the center? I.e. I want to make sure
that each point in the output only has information about the past and
knows nothing about the future, with respect to that time. Is there a
simple way to do this?

Aaron Schurger, PhD
Senior researcher
Laboratory of Cognitive Neuroscience
Brain-Mind Institute, Department of Life Sciences
École Polytechnique Fédérale de Lausanne
Station 19, AI 2101
1015 Lausanne, Switzerland
+41 21 693 1771
aaron.schurger at epfl.ch

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