# (Fourier Transform) What does F(j) represent in frequency domain?

Discussion in 'Math' started by spark360z, Nov 30, 2012.

1. ### spark360z Thread Starter New Member

Jul 27, 2012
10
0
I'm trying to understand the concept of Fourier transform and get stuck on something very simple.

My question is, what does F(jω) represent in frequency domain?

If I have a voltage source v(t), v(t) represents voltage as a function of time, therefore I know the voltage at any given time.

But in frequency domain, thing seems to be different.

Let say the transformed signal is V(jω). Let say at ω=2pi(1000), substitute ω in V(jω), suppose I get V(jω)=V(j2pi(1000))=10

What does "10" represent?

Is it an amplitude of a sinusoidal at 1000 Hz? Therefore the signal has sinusoidal 1k Hz frequency amplitude=10 as a component?

2. ### spark360z Thread Starter New Member

Jul 27, 2012
10
0
What is the unit of V(jω)? Is it a voltage?

3. ### Wendy Moderator

Mar 24, 2008
20,772
2,540
It is more of a phase I think. j is an imaginary number (square root of -1). 2ω is 2 ∏ f (2 X Pi X frequency).

4. ### MrChips Moderator

Oct 2, 2009
12,652
3,461
You are correct.

See this: http://www.neurophys.wisc.edu/comp/docs/not012.html