NawfalMotii79
42 lines
988 B
Python
42 lines
988 B
Python
import numpy as np
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from numpy.fft import fft, ifft
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import matplotlib.pyplot as plt
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fs=125*pow(10,6) #sampling frequency
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Ts=1/fs # sampling time
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Tb=0.5*pow(10,-6) # burst time
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Tau=900*pow(10,-6) # pulse repetition time
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fmax=30*pow(10,6) # maximum frequency on ramp
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fmin=10*pow(10,6) # minimum frequency on ramp
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n=int(Tb/Ts) # number of samples per ramp
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N = np.arange(0, n, 1)
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theta_n= 2*np.pi*(pow(N,2)*pow(Ts,2)*(fmax-fmin)/(2*Tb)+fmin*N*Ts) # instantaneous phase
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y = 1 + np.sin(theta_n) # ramp signal in time domain
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t = Ts*np.arange(0,n,1)
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Y = fft(y)
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M =len(Y)
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m = np.arange(M)
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T = M*Ts
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freq = m/T
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plt.figure(figsize = (12, 6))
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plt.subplot(121)
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plt.stem(freq, np.abs(Y), 'b', \
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markerfmt=" ", basefmt="-b")
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plt.xlabel('Freq (Hz)')
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plt.ylabel('FFT Amplitude |Y(freq)|')
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plt.xlim(0, (1.3*fmax))
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plt.ylim(0, 60)
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plt.subplot(122)
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plt.plot(t, ifft(Y), 'r')
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plt.xlabel('Time (s)')
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plt.ylabel('Amplitude')
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plt.tight_layout()
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plt.show()
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