Numpy fftshift

1. What does Numpy Fftshift do?
2. How do you use Fftshift?
3. Should I use Fftshift?
4. What does Numpy FFT Fftfreq do?

What does Numpy Fftshift do?

Shift the zero-frequency component to the center of the spectrum. This function swaps half-spaces for all axes listed (defaults to all). Note that y[0] is the Nyquist component only if len(x) is even.

How do you use Fftshift?

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.

Should I 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.

What does Numpy FFT Fftfreq do?

fft. fftfreq. Return the Discrete Fourier Transform sample frequencies.