Waves_ex3a

import numpy as np
import matplotlib.pyplot as plt

w1 = 5 #1st freq
w2 = 7 # 2nd freq
t_f = 10 # timespan

t = np.arange(0,t_f,0.001)

wave_a = np.cos( w1*t )
wave_b = np.cos( w2*t )
wave_sum = np.cos( w1*t ) + np.cos( w2*t )
wave_product = 2* np.cos(( w1 + w2)*t/2 ) * np.cos( (w1-w2)*t/2 )

plt.figure(1) # initialisierung
p = plt.subplot(3,1,1)
plt.plot(t,wave_a,label=str(w1)+" Hz")
plt.plot(t,wave_b,label=str(w2)+" Hz")
plt.legend(bbox_to_anchor=(0., 1.02, 1., .102), loc=3,
           ncol=2, mode="expand", borderaxespad=0.)

p = plt.subplot(3,1,2)
plt.plot(t,wave_sum,label="Summe = cos( w1*t ) + cos( w2*t )")
plt.legend(bbox_to_anchor=(0., 1.02, 1., .102), loc=3,
           ncol=2, mode="expand", borderaxespad=0.)

p = plt.subplot(3,1,3)
plt.plot(t,wave_product,label="Produkt = 2* cos( (w1 + w2)*t/2 ) * cos( (w1-w2)*t/2 )")
plt.legend(bbox_to_anchor=(0., 1.02, 1., .102), loc=3,
           ncol=2, mode="expand", borderaxespad=0.)

plt.tight_layout()
plt.show()