rfftfreq — SciPy v1.15.3 Manual (original) (raw)

scipy.fftpack.

scipy.fftpack.rfftfreq(n, d=1.0)[source]#

DFT sample frequencies (for usage with rfft, irfft).

The returned float array contains the frequency bins in cycles/unit (with zero at the start) given a window length n and a sample spacing d:

f = [0,1,1,2,2,...,n/2-1,n/2-1,n/2]/(dn) if n is even f = [0,1,1,2,2,...,n/2-1,n/2-1,n/2,n/2]/(dn) if n is odd

Parameters:

nint

Window length.

dscalar, optional

Sample spacing. Default is 1.

Returns:

outndarray

The array of length n, containing the sample frequencies.

Examples

import numpy as np from scipy import fftpack sig = np.array([-2, 8, 6, 4, 1, 0, 3, 5], dtype=float) sig_fft = fftpack.rfft(sig) n = sig_fft.size timestep = 0.1 freq = fftpack.rfftfreq(n, d=timestep) freq array([ 0. , 1.25, 1.25, 2.5 , 2.5 , 3.75, 3.75, 5. ])