Plot Fourier Transformation
DESCRIPTION:
Create a plot of the Fourier transform of a function.

This function is generic (see Methods); method functions can be written to handle specific classes of data. Classes which already have methods for this function include:

wavelet.packet, wp.atom.

USAGE: 
fourier.transform.plot(y, x=NULL, plot=T, phase=F, J=NULL, ...)
REQUIRED ARGUMENTS:
y:
any S-PLUS object.
OPTIONAL ARGUMENTS:
x:
a vector at which the Fourier transform will be computed. see below for details.
plot:
logical flag: if TRUE, a plot is created.
phase:
logical flag indicating whether phase is plotted. The default is phase=FALSE.
J:
a positive integer, serves as the number of iterations in the computation. The default is J=8+log(max(2,abs(x/pi)),2).

Graphical parameters may also be supplied as arguments to this function (see par).

SIDE EFFECTS:
a plot is produced.
VALUE:
a vector of mode complex.
DETAILS:
See the printed help file for the definition of The Fourier transform of filter f at x.
SIDE EFFECTS:
if plot=TRUE, a plot of the modulii of Fourier transform is created on the current graphics device.
SEE ALSO:
transfer.plot , wavelet.packet , wp.atom .