scipy.fftpack.
rfftfreq#
- 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]/(d*n) if n is even f = [0,1,1,2,2,...,n/2-1,n/2-1,n/2,n/2]/(d*n) 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. ])