# fourier (power) property?

• May 8th 2010, 07:03 AM
diz
fourier (power) property?
Hi all,

In a course I am doing I have the following tutorial question (from a CTFS lecture):

Let f(x) be a signal, and F(s) be is it's Fourier transform.
What then is the Fourier transform of:
exp(4 pi j t f(x))
?

I have scoured books and the net for some property of the FT than will cover this - I'm now starting to think this question may be a typo, with f(x) intended to be outside the exp().
To put it in some context, this question is one part of a five part question. The other four parts are all answered by straight forward use of some common Fourier property.

I'm almost certain it is irrelevant, but I have been given a sketch of F(s) (for the CTFT of f(x) ), it can be described using a few heaviside functions as =u(s)+u(s-1)+u(s-2) -u(s-3)

Any help or opinions would be much appreciated!
diz.
• May 9th 2010, 02:06 AM
CaptainBlack
Quote:

Originally Posted by diz
Hi all,

In a course I am doing I have the following tutorial question (from a CTFS lecture):

Let f(x) be a signal, and F(s) be is it's Fourier transform.
What then is the Fourier transform of:
exp(4 pi j t f(x))
?

I have scoured books and the net for some property of the FT than will cover this - I'm now starting to think this question may be a typo, with f(x) intended to be outside the exp().
To put it in some context, this question is one part of a five part question. The other four parts are all answered by straight forward use of some common Fourier property.

I'm almost certain it is irrelevant, but I have been given a sketch of F(s) (for the CTFT of f(x) ), it can be described using a few heaviside functions as =u(s)+u(s-1)+u(s-2) -u(s-3)

Any help or opinions would be much appreciated!
diz.

I would put my money on a typo.

CB
• May 10th 2010, 10:56 PM
diz
Thanks CB.

A typo was the scenario I went with in the end, lets see what the lecturer thinks!

p.s. If anyone does have a 'not horribly complex' solution for this I'd be interested to know - after spending many hours on it, curiosity has me..