Book Image

Sage Beginner's Guide

By : Craig Finch
1 (1)
Book Image

Sage Beginner's Guide

1 (1)
By: Craig Finch

Overview of this book

Table of Contents (17 chapters)
Sage Beginner's Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Time for action – plotting a list


Sometimes, you need to plot a list of discrete data points. The following example might be found in an introductory digital signal processing (DSP) course. We will use lists to represent digital signals. We sample the analogue function cosine(t) at two different sampling rates, and plot the resulting digital signals.

# Use list_plot to visualize digital signals
# Undersampling and oversampling a cosine signal

sample_times_1 = srange(0, 6*pi, 4*pi/5)
sample_times_2 = srange(0, 6*pi, pi/3)
data1 = [cos(t) for t in sample_times_1]
data2 = [cos(t) for t in sample_times_2]

plot1 = list_plot(zip(sample_times_1, data1), color='blue')
plot1.axes_range(0, 18, -1, 1)
plot1 += text("Undersampled", (9, 1.1), color='blue', fontsize=12)
plot2 = list_plot(zip(sample_times_2, data2), color='red')
plot2.axes_range(0, 18, -1, 1)
plot2 += text("Oversampled", (9, 1.1), color='red', fontsize=12)

g = graphics_array([plot1, plot2], 2, 1) # 2 rows, 1 column
g.show(gridlines=...