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+Agenda¶
-
+
- What are radio waves? +
- Hardware radios +
+
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+
+
+Radio Waves¶
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+
+
+In [3]:
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+
+import numpy as np
+import matplotlib.pyplot as plt
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+
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+In [4]:
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+
+
+modulator_frequency = 4.0
+carrier_frequency = 40.0
+modulation_index = 1.0
+size = 44100.0 * 2
+
+time = np.arange(size) / size
+modulator = np.sin(2.0 * np.pi * modulator_frequency * time) * modulation_index
+carrier = np.sin(2.0 * np.pi * carrier_frequency * time)
+
+product = np.zeros_like(modulator)
+for i, t in enumerate(time):
+ product[i] = np.sin(2. * np.pi * (carrier_frequency * t + modulator[i]))
+
+modulator = np.sin(2.0 * np.pi * modulator_frequency * time) * modulation_index
+amp = np.zeros_like(modulator)
+for i, t in enumerate(time):
+ amp[i] = np.sin(2. * np.pi * (carrier_frequency * t * modulator[i]))
+
+
+
+
+
+In [5]:
+
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+
+
+plt.subplot(4, 1, 1)
+plt.title('Frequency Modulation')
+plt.plot(modulator)
+plt.ylabel('Amplitude')
+plt.xlabel('Modulator signal')
+
+plt.subplot(4, 1, 2)
+plt.plot(carrier)
+plt.ylabel('Amplitude')
+plt.xlabel('Carrier signal')
+
+plt.subplot(4, 1, 3)
+plt.plot(product)
+plt.ylabel('Amplitude')
+plt.xlabel('Output signal')
+
+plt.subplot(4, 1, 4)
+plt.plot(modulator * carrier)
+plt.ylabel('Amplitude')
+plt.xlabel('Output signal')
+plt.show()
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