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.