Howtosignalprocessing
- What is the difference between FFT and Fftshift?
- What does Fftshift do in MATLAB?
- Do I need to use Fftshift?
- How do you use Fftshift and Ifftshift?
What is the difference between FFT and Fftshift?
fft computes the discrete Fourier transform and by definition the output is complex. fftshift doesn't compute anything except swaping the position of the samples, so if your input is real, you get real output.
What does Fftshift do in MATLAB?
Y = fftshift( X ) rearranges a Fourier transform X by shifting the zero-frequency component to the center of the array. If X is a vector, then fftshift swaps the left and right halves of X . If X is a matrix, then fftshift swaps the first quadrant of X with the third, and the second quadrant with the fourth.
Do I need to use Fftshift?
It depends on what you are going to do with the transformed data. If you don't perform an fftshift before transforming, the fft result will have every other value multiplied by -1. This doesn't matter if you plan to view the magnitude or magnitude squared of the result.
How do you use Fftshift and Ifftshift?
You can use the fftshift and ifftshift functions to swap left and right halves of a vector. Create a vector containing an odd number of elements, and swap the left and right sides of the vector using the fftshift function. Use the ifftshift function to swap the left and right sides of X .
