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Re: using iFFT on a Continuous Time Transfer Function

• To: mathgroup at smc.vnet.net
• Subject: [mg48734] Re: using iFFT on a Continuous Time Transfer Function
• From: "Mariusz Jankowski" <mjankowski at usm.maine.edu>
• Date: Fri, 11 Jun 2004 23:59:02 -0400 (EDT)
• Organization: University of Southern Maine
• References: <ca6hrm$g76$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Vin, if you have an analytic expression why not try InverseFourierTransform.
Go to Help Browser, look in Algebraic Computation -> Calculus ->
InverseFourierTransform.

Mariusz



>>> Vin<car_d_active_unit at hotmail.com> 6/9/2004 4:30:46 AM >>>
Hello,

I know what my signal looks like in the frequency domain, because I
have a analytic expression for that (i.e., a function of frequency). I
don't have a time domain counterpart though, but I expect it to be a
real valued pulse-like signal, lasting a few nanoseconds.

I am wondering, can I somehow apply the IFFT to this frequency domain
function to get a discrete time representation of the time domain
counterpart?

If so, any hints as to how to go about it?

I have already tried sampling my frequency domain function to produce
something like the output of a FFT, e.g., with the -ve frequency
function values being generated from the complex conjugate of the
positive frequency function values etc. However, when I apply the
IFFT, I get nothing like what I expect.

thanks for any help

Vin