spkit.sinc_interp

spkit.sinc_interp(x)

Sinc interpolation

Upsampling input signal with a factor of 2

Using FFT approach to smooth the interpolated zeros.

Parameters:
x: 1d-array

  • input signal, with length of n

Returns:
y: 1d-array

  • upsampled by factor of 2, with length of 2*n -1

Notes

There are effects on boundary

Examples

#sp.sinc_interp
import numpy as np
import matplotlib.pyplot as plt
import spkit as sp
fs=50
x = sp.create_signal_1d(n=50,seed=2,sg_winlen=20)
y = sp.sinc_interp(x.copy())
t = np.arange(len(x))/fs
t0 = np.arange(len(y))/(2*fs)
plt.figure(figsize=(10,2))
plt.plot(t0,y.real,'.',alpha=0.5, label=f'y (n={len(y)})')
plt.plot(t,x,'.',alpha=0.5,label=f'x (n={len(x)})')
plt.xlabel('time (s)')
plt.legend()
plt.show()
../../_images/spkit-sinc_interp-1.png