title: How to print a amplitude modulated signal using python
body: <p>I have an matlab example of this program but I can't do it in Python.
  How it must look like (mathlab example) <a href="https://imgur.com/a/oam3jXl" rel="nofollow noreferrer">https://imgur.com/a/oam3jXl</a>.</p>
  
  <pre class="lang-py prettyprint-override"><code>import numpy as np
  import matplotlib.pyplot as plt
  from scipy.signal import hilbert, chirp
  duration = int(input("Input duration of signal = "))
  A = int(input("Input amplitude of signal = "))
  start = int(input("Input start of modulation time = "))
  end = int(input("Input lenght of modulation = "))
  fs = 400.0
  samples = int(fs*duration)
  t = np.arange(samples) / fs
  main_t = []
  result = []
  counter=0
  for l in range(0,samples):
      main_t.append(0)
      result.append(0)
  start_mod = np.arange(start*fs)
  end_mod = np.arange(end*fs)
  signal = chirp(t, 20.0, t[-1], 100.0)
  signal *= (A + 0.5 * np.sin(2.0*np.pi*3.0*t) )
  
  for i in np.arange(0,start*fs):
      signal.insert(i,0)
  
  fig = plt.figure()
  ax0 = fig.add_subplot(211)
  ax0.plot(main_t, result)
  ax0.set_xlabel("time in seconds")
  plt.show()
  </code></pre>
  
  <p>I expect the inputing  some data from console and then print graph using matplotlib for example. Graph must look like graph that u can see on image(mathlab example).</p>