from numpy import hanning
hanning(12)
# array([ 0.        ,  0.07937323,  0.29229249,  0.57115742,  0.82743037,
# 0.97974649,  0.97974649,  0.82743037,  0.57115742,  0.29229249,
# 0.07937323,  0.        ])

# Plot the window and its frequency response:

from numpy.fft import fft, fftshift
import matplotlib.pyplot as plt

window = np.hanning(51)
plt.plot(window)
plt.title("Hann window")
plt.ylabel("Amplitude")
plt.xlabel("Sample")
plt.show()

plt.figure()
A = fft(window, 2048) / 25.5
mag = abs(fftshift(A))
freq = np.linspace(-0.5,0.5,len(A))
response = 20*np.log10(mag)
response = np.clip(response,-100,100)
plt.plot(freq, response)
plt.title("Frequency response of the Hann window")
plt.ylabel("Magnitude [dB]")
plt.xlabel("Normalized frequency [cycles per sample]")
plt.axis('tight')
plt.show()