Pretty much all of Fall 2024

7th-Semester-Fall-2024/ECOMMS/labs/lab1/part3.py

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+import numpy as np
+import matplotlib.pyplot as plt
+import scipy as sp
+
+f_m = 5E3
+f_c = 25E3
+
+f_s = 50*f_c
+
+T_m = 1/f_m
+T_c = 1/f_c
+T_s = 1/f_s
+
+A_c = 10
+A_m = 1
+
+t = np.arange(0,2*T_m,T_s)
+f = t*f_s/(2*T_m)
+
+# ===== AM =====
+s = A_c * (1 + A_m*np.cos(2*np.pi*f_m*t)) * np.cos(2*np.pi*f_c*t)
+
+var_s = np.cov(s)
+
+SNR = 10
+var_snr = var_s/(10**(SNR/10))
+noise_snr = (var_snr**0.5) * np.random.randn(len(s))
+m = s+noise_snr
+
+S = sp.fft.fft(s)
+M = sp.fft.fft(m)
+
+plt.subplot(211)
+plt.stem(f, S)
+plt.subplot(212)
+plt.stem(f, M)
+plt.show()
+
+# ===== FM =====
+beta_f = 10
+s = A_c*np.cos(2*np.pi*f_c*t + beta_f*A_m*np.sin(2*np.pi*f_m*t))
+
+var_snr = var_s/(10**(SNR/10))
+noise_snr = (var_snr**0.5) * np.random.randn(len(s))
+m = s+noise_snr
+
+S = sp.fft.fft(s)
+M = sp.fft.fft(m)
+
+plt.subplot(211)
+plt.stem(f, S)
+plt.subplot(212)
+plt.stem(f, M)
+plt.show()