# -*- coding: utf-8 -*-

import math
from numpy import arange
import numpy as numpy
from matplotlib.pyplot import  plot, show
import matplotlib.pyplot as plt
import pylab

tcar = arange(0.0,20.0,0.01)
car = []
i=0.5
for t in tcar:
	if t%4==0: i=-i
	car.append(i)
	
ttri = arange(20.0,56.0,8)
tri = []
i=-i
for t in ttri:
	i=-i
	tri.append(i)

sci=[]
tsci = [52,52.01]
for a in range(0,6):
	tsci.append(tsci[a]+10)
for t in tsci:
	sci.append(i)
	i = -i

timp=[82,90,90.01,100,100.1,108,108.1,120]
imp=[0.5,0.5,0,0,0.5,0.5,0,0]

fig = plt.figure()
ax1 = fig.add_subplot(111)
ax1.set_ylabel('Temps (s)')
ax1.plot(tcar,car,"b")

ax2 = fig.add_subplot(111)
ax2.plot(ttri,tri,"r")

ax3 = fig.add_subplot(111)
ax3.set_xlabel('Tension (volts)')
ax3.plot(tsci,sci,"g")

ax4 = fig.add_subplot(111)
ax4.set_ylabel('Tension (volts)')
ax4.plot(timp,imp,"b")

ax1.text(1, -0.55, u"Signal carré")
ax2.text(22, -0.55, u"Signal triangulaire")
ax3.text(51, -0.55, u"Signal en dents de scie")
ax4.text(83, -0.1, u"Signal\nimpulsionnel")

plt.axis([0,110,-0.6,0.6])
plt.grid(True)
plt.savefig('signaux_alternatifs.svg' ,transparent=False)