Discrete Fourier Transform Frequency

  • #1

Main Question or Discussion Point

Hi everybody,

I'm in the process of writing a discrete Fourier transform program using the algorithm on the DFT wikipedia page. When I throw in functions that I know the frequency domain signal of it gives the predicted shape but I have absolutely know idea how to generate a frequency axis.

Does anybody here know how I can compute the frequency values?

Thanks in advance.

Chris
 

Answers and Replies

  • #2
Redbelly98
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
12,100
129
Try using a sine function at a specific frequency. Then whatever you get for the Fourier Transform corresponds to that frequency.
 
  • #3
jbunniii
Science Advisor
Homework Helper
Insights Author
Gold Member
3,394
180
Hi everybody,

I'm in the process of writing a discrete Fourier transform program using the algorithm on the DFT wikipedia page. When I throw in functions that I know the frequency domain signal of it gives the predicted shape but I have absolutely know idea how to generate a frequency axis.

Does anybody here know how I can compute the frequency values?

Thanks in advance.

Chris
The DFT gives you N evenly spaced samples of the DTFT (discrete-time Fourier transform). The frequencies corresponding to these samples are

[tex]\frac{n}{N} F_s[/tex]

where [itex]n = 0,1,\ldots,N-1[/itex] are the indices of the samples, and [itex]F_s[/itex] is the sampling frequency of the input sequence.
 

Related Threads on Discrete Fourier Transform Frequency

Replies
1
Views
3K
Replies
5
Views
7K
Replies
1
Views
2K
  • Last Post
Replies
15
Views
2K
Replies
1
Views
1K
Replies
10
Views
2K
Replies
2
Views
1K
Replies
8
Views
4K
Replies
2
Views
4K
Replies
5
Views
6K
Top