1. CTU: EE 343 – Signals and Systems: Lab 1: Continuous and Discrete Time Signals in MATLAB 1
Colorado Technical University
EE 343 – Signals and Systems
Lab 1: Continuous and Discrete Time Signals
May 2010
Loren Schwappach
ABSTRACT: This lab report was completed as a course requirement to obtain full course credit in EE343, Signals
and Systems at Colorado Technical University. This lab report examines the basic operations of MATLAB via the creation of
several continuous-time and discrete-time signals. If you have any questions or concerns in regards to this laboratory
assignment, this laboratory report, the process used in designing the indicated circuitry, or the final conclusions and
recommendations derived, please send an email to LSchwappach@yahoo.com. All computer drawn figures and pictures used
in this report are of original and authentic content.
III. RESULTS
I. INTRODUCTION For the discrete-time function: , the
MATLAB is a powerful program and is useful in the following code was input into MATLAB:
visualization of mathematics, physics, and applied
engineering. In this lab exercise MATLAB will be used to %Setup a matrix of discrete values ones and zeros.
compute and visualize discrete-time and continuous-time %The graph starts at t=1 so four zeros are required.
signals. >> stepfn =[zeros(1,4),ones(1,5)]
stepfn =
0 0 0 0 1 1 1 1 1
%Multiply all values by 4.
II. PROCEDURES >> Y = 4*stepfn
This lab begins with the creation of the discrete-time Y=
step function: 0 0 0 0 4 4 4 4 4
>> stem(Y)
To create this discrete time function in MATLAB,
individual values are defined at each time and inserted into a
MATLAB array. These values used must be numerous enough
to efficiently describe the function with great accuracy, and
for our first function, 9 values were placed within an array.
The second objective of this lab is to develop and
plot the continuous-time sinusoidal function:
To create this function in MATLAB a variable name is
created and equated to the function. In the above case the
function y[t] is a combination of two added cosine functions.
The final objective of this lab is to develop a discrete-
time representation of the continuous-time function
mentioned previously. Figure 1: Discrete-time step function
As can be seen by figure 1, the function is a discrete-
time representation of a step function with a height of 4.

2. CTU: EE 343 – Signals and Systems: Lab 1: Continuous and Discrete Time Signals in MATLAB 2
For the continuous-time function: IV. EVALUATION
, the following MATLAB code
. Developing the continuous-time and discrete-time
was used.
signals in MATLAB was an easy task and no difficulties were
encountered. I was able to plot multiple cosine functions
>> t = 0:.00001:.1;
within the same graph as shown in figure 2. All plots were
>> w0 = 2*pi;
smooth and easy to manipulate.
>> Y1 = (cos(w0*50*t));
>> Y2 = 2*cos(w0*100*t);
>> Y = Y1 + Y2; V. CONCLUSIONS
>> plot(t,Y1,'--', t,Y2,':', t,Y,'-'); . MATLAB is a great utility for representing complex
concepts visually and can easily be manipulated to show
signals in various formats. This lab project was successful in
demonstrating MATLABs powerful features in a quick and
easy method.
REFERENCES
[1] Haykin, S., “Signals and Systems 2nd Edition” McGraw-
Hill, New York, NY, 2007.
Figure 2: Continuous-time functions
Finally, the continuous-time function Y in figure 2
above can now be represented in MATLAB by:
>> t = 0:.001:.1;
>> w0 = 2*pi;
>> Y1 = (cos(w0*50*t));
>> Y2 = 2*cos(w0*100*t);
>> Y = Y1 + Y2;
>> stem(t,Y);
Figure 3: Discrete-time representation of y[t]