import matplotlib.pyplot as plt
from numpy import arange
from sk_dsp_comm.sigsys import step
t = arange(-1,5,.01)
x = step(t)
plt.plot(t,x)
plt.ylim([-0.01, 1.01])
plt.show()
#
# To turn on at t = 1, shift t.
#
x = step(t - 1.0)
plt.ylim([-0.01, 1.01])
plt.plot(t,x)