%matplotlib inline

import numpy as np
import matplotlib.pyplot as plt


def switch_on(x, x0, slope=20):
    """ 
    switch from 0 to 1 at x0
    
    Parameters
    ----------
    
    slope : float
        defines how steep is the switching function
    """
    return 1/( 1+ np.exp(slope*(x-x0)) )

def switch_off(x, x0, slope=20):
    """
    switch from 1 to 0 at x0
    """
    
    return 1 - switch_on(x, x0, slope)
    

N = 1000

tt = np.linspace(-10, 10, N)
tt = np.linspace(0, 3.5, N)

# on_off_on

yy1 = switch_on(tt, 0.9)

yy2 = switch_off(tt, 2.1)

yy3 = switch_on(tt, 0.9) + switch_off(tt, 2.1) 


plt.plot(tt, yy1)
plt.plot(tt, yy2)
offset = 0.3  # for better visability
plt.plot(tt, yy3 + offset)


signal = np.sinc(5*(tt - 1.6)) * 100
signal_mod = signal * yy3

plt.figure()

plt.plot(tt, signal, lw=0.2)
plt.plot(tt, signal_mod)