import numpy as np

from matplotlib import pyplot as plt

"""

Description:

Make sure the windowing effects are well-understood

Date:

3/9/2021

Author: Hunter Akins

Institution: Scripps Institution of Oceanography, UC San Diego

"""

from scipy.signal.windows import get_window

window_len = 1500

N_fft = 4*8096

hamm = get_window('hamming', window_len)

transfer_func = np.fft.fft(hamm)

freqs = np.fft.fftfreq(window_len, 1/1500)

transfer_func = np.square(abs(transfer_func))

transfer_func /= np.max(transfer_func)

trans_db = 10*np.log10(transfer_func)

plt.figure()

plt.plot(freqs, trans_db)

hamm_pad = np.pad(hamm, (0, N_fft-window_len),'constant')

transfer_func = np.fft.fft(hamm_pad)

freqs = np.fft.fftfreq(N_fft, 1/1500)

transfer_func = np.square(abs(transfer_func))

transfer_func /= np.max(transfer_func)

trans_db = 10*np.log10(transfer_func)

plt.plot(freqs, trans_db)

plt.show()