general_cosine(M, a, sym=True)
Number of points in the output window
Sequence of weighting coefficients. This uses the convention of being centered on the origin, so these will typically all be positive numbers, not alternating sign.
When True (default), generates a symmetric window, for use in filter design. When False, generates a periodic window, for use in spectral analysis.
The array of window values.
Generic weighted sum of cosine terms window
HFT90D = [1, 1.942604, 1.340318, 0.440811, 0.043097]
import numpy as np
from scipy.signal.windows import general_cosine
from scipy.fft import fft, fftshift
import matplotlib.pyplot as plt
window = general_cosine(1000, HFT90D, sym=False)
plt.plot(window)
plt.title("HFT90D window")
plt.ylabel("Amplitude")
plt.xlabel("Sample")
plt.figure()
A = fft(window, 10000) / (len(window)/2.0)
freq = np.linspace(-0.5, 0.5, len(A))
response = np.abs(fftshift(A / abs(A).max()))
response = 20 * np.log10(np.maximum(response, 1e-10))
plt.plot(freq, response)
plt.axis([-50/1000, 50/1000, -140, 0])
plt.title("Frequency response of the HFT90D window")
plt.ylabel("Normalized magnitude [dB]")
plt.xlabel("Normalized frequency [cycles per sample]")
plt.axhline(-90.2, color='red')
plt.show()
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scipy.signal.windows._windows:get_window
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