38 lines
529 B
Python
38 lines
529 B
Python
import numpy as np
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import scipy as sp
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import matplotlib.pyplot as plt
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A_c = 1
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f_1 = 500
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T_1 = 1/f_1
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omega_1 = 2*np.pi*f_1
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f_c = 20000
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T_c = 1/f_c
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omega_c = 2*np.pi*f_c
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def m(t):
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return 2*np.cos(2*omega_1*t) + 3*np.cos(3*omega_1*t)
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def s(t):
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return A_c*m(t)*np.cos(omega_c*t)
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f_s = 40*f_c
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T_s = 1/f_s
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t = np.arange(0,T_1,T_s)
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plt.plot(t,s(t))
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plt.plot(t,m(t))
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plt.show()
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S = sp.fft.fft(s(t))[35:45]
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f = t*f_s/T_1
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f = f[35:45]
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for i in range(len(f)):
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print(f[i], S[i].real)
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plt.stem(f,S.real/1600)
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plt.show()
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