# Homework Help: Fourier transform of function times periodic function

1. May 13, 2014

### aaaa202

Suppose I have a function of the type:

h(t) = g(t)f(t)

where g(t) is a periodic function. Are there any nice properties relating to the fourier transform of such a product?

Edit: If not then what about if g(t) is taken as the complex exponential?

2. May 13, 2014

### Staff: Mentor

Not sure about your first question, but if
$$h(t) \Leftrightarrow H(f)$$
is a transform pair, then
$$h(t) e^{-2 \pi i f_0 t} \Leftrightarrow H(f - f_0)$$
and its called frequency shifting (taken from Numerical Recipes in C).