Can we draw digital waveform graph with Pyplot in python or Matlab?


I am trying to draw digital signal waveform graph for bits like 01010101010101 using pyplot in python, like

http://upload.wikimedia.org/wikipedia/commons/thumb/5/50/Differential_manchester_encoding.svg/600px-Differential_manchester_encoding.svg.png

Is it possible with Pyplot?


Answers:


As noted by tcaswell, the right function to use is step. Here an example that approximates your given plot:

import matplotlib.pyplot as plt
import numpy as np

def my_lines(ax, pos, *args, **kwargs):
    if ax == 'x':
        for p in pos:
            plt.axvline(p, *args, **kwargs)
    else:
        for p in pos:
            plt.axhline(p, *args, **kwargs)

bits = [0,1,0,1,0,0,1,1,1,0,0,1,0]
data = np.repeat(bits, 2)
clock = 1 - np.arange(len(data)) % 2
manchester = 1 - np.logical_xor(clock, data)
t = 0.5 * np.arange(len(data))

plt.hold(True)
my_lines('x', range(13), color='.5', linewidth=2)
my_lines('y', [0.5, 2, 4], color='.5', linewidth=2)
plt.step(t, clock + 4, 'r', linewidth = 2, where='post')
plt.step(t, data + 2, 'r', linewidth = 2, where='post')
plt.step(t, manchester, 'r', linewidth = 2, where='post')
plt.ylim([-1,6])

for tbit, bit in enumerate(bits):
    plt.text(tbit + 0.5, 1.5, str(bit))

plt.gca().axis('off')
plt.show()

enter image description here