Tuesday, 14 March 2017

Expt. 3 Fast Fourier Transform

The FFT algorithm divides the N-point input signal into 2 parts-even and odd signal values of the input. Computation is carried out only for N/2 signal values, this increases the speed of computations.

The input & output sequence are in a bit reversed manner.

In this lab session we studied and executed FFT of 4 point and 8 point sequence using DITFFT.

We also calculated no. of computations required to find out FFT of a sequence. Comparing it with that of DFT, we can conclude that FFT is much faster.

12 comments:

  1. Can you post why FFT is faster than DFT?

    ReplyDelete
  2. FFT is computationally fast, since calculations are performed parallely.

    ReplyDelete
  3. Fast Fourier Transform are not suitable for real time applications. FFT algorithms are implemented using parallel processing techniques.

    ReplyDelete
  4. FFT reduces complex multiplications by decimating the signal to a lower radix.

    ReplyDelete
  5. They cannot be used to find the output of real time system because entire input is not available at an instance of time

    ReplyDelete
  6. Number of computations in FFT is less than that of DFT. This makes FFT computationally faster.

    ReplyDelete
  7. For a better understanding of FFT refer the link below:
    Link: http://www.earlevel.com/main/2002/08/31/a-gentle-introduction-to-the-fft/

    ReplyDelete
  8. State the Limitations of FFT algorithm?

    ReplyDelete
  9. Why FFT cannot be used for real time applications

    ReplyDelete
  10. the signal is divided into 2 parts, so the computation is carried out only for N/2 signal values

    ReplyDelete
  11. This comment has been removed by a blog administrator.

    ReplyDelete
  12. For real time implementation using FFT entire input signal must be available because FFT is parallel computation

    ReplyDelete