Introduction to MATLAB - Continuous and Discrete Time Signals and Systems - page 843

3 3

2 2

1 1

0 0

−1 −1

−2 −2

−3

−3

−20 −10 0 10 20 −20 −10 0 10 20

k k

(a) (b)

Fig. E.1. Plots of
f [ k ] = 2 cos(0.5 k ) versus k in
the range −20 ≤ k ≤ 20.
(a) CT plot; (b) stem DT plot.

% [x-min x-max y-min y-max]

>> print -dtiff plot.tiff % Saves figure in the file

% “plot.tiff” in
% the TIFF format

These instructions produce a continuous plot cosine wave, as shown in
Fig. E.1. It is also possible to construct a discrete-time plot using the stem
function:

>> figure(2)
>> stem(k,f,'filled');

% DT plot; option 'filled'
% fills the circles at the
% top of vertical bars

>> xlabel('k'); % Sets label of X-axis to k

>> ylabel('f[k]'); % Sets label of Y-axis to f[k]

>> axis([-25 25 -3 3])
>> print -dtiff plot2.tiff

Both plot and stem functions have a variety of options available, which may
be selected to change the appearance of the figures. The reader is encouraged
to explore these options by seeking help on these functions in M ATLAB .In
addition, there are several other 2D graphical functions in M ATLAB . These
include semilogx , semilogy , loglog , bar , hist , polar , stairs ,
rose , errorbar , compass , and pie .