| stft {e1071} | R Documentation |
This function computes the Short Time Fourier Transform
of a given vector X.
First, time-slices of length win are
extracted from the vector. The shift of one time-slice to the next one is
given by inc. The values of these time-slices are smoothed by
mulitplying them with a window function specified in wtype. For
the thus obtained windows, the Fast Fourier Transform is computed.
stft(X, win=min(80,floor(length(X)/10)), inc=min(24, floor(length(X)/30)), coef=64, wtype="hanning.window")
X |
The vector from which the stft is computed. |
win |
Length of the window. For long vectors the default window size is 80, for short vectors the window size is chosen so that 10 windows fit in the vector. |
inc |
Increment by which the window is shifted. For long vectors the default increment is 24, for short vectors the increment is chosen so that 30 increments fit in the vector. |
coef |
Number of Fourier coefficients |
wtype |
Type of window used |
Object of type stft. Contains the values of the stft and information about the parameters.
values |
A matrix containing the results of the stft. Each row of
the matrix contains the coef Fourier coefficients of one
window. |
windowsize |
The value of the parameter win |
increment |
The value of the parameter inc |
windowtype |
The value of the parameter wtype |
Andreas Weingessel
plot.stft
x<-rnorm(500) y<-stft(x) plot(y)