Signals and Systems - Electrical Engineering

42 C H A P T E R 0: From the Ground Up!

where we usewhosto check its size:

Name Size Bytes Class

xy 121x2 1936 double array

Grand total is 242 elements using 1936 bytes

This indicates that the arrayxyhas 121 rows and 2 columns, the first colum corresponding tox, the

degree values, and the second column corresponding to the sine values,y. Verify this and plot the

values by using

x = xy(:, 1);

y = xy(:, 2);

stem(x, y)

Finally, MATLAB provides some data files for experimentation and you only need to load them. The

following “train.mat” is the recording of a train whistle, sampled at the rate ofFssamples/sec, which

accompanies the sampled signaly(n)(see Figure 0.19).

clear all

load train

whos

Name Size Bytes Class

Fs 1x1 8 double array

y 12880x1 103040 double array

Grand total is 12881 elements using 103048 bytes

sound(y, Fs)

plot(y)

FIGURE 0.19

Train signal.

0 2000 4000 6000 8000 10000 12000

− 1

−0.5

0

0.5

1

n (samples)

y[

n]