1. Net 222: Communications and networks fundamentals (Practical Part)
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Lab 3: Matlab – Sinusoidal

2. Sinusoidal Time & Frequency domain continuous or discrete signals
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3. continuous or discrete signals
Continuous-Time Signals:
A signal is continuous-time signal if the independent variable t is continuous.
Discrete-Time Signals:
A signal is defined at discrete times, a discrete-time signal is often identified as a sequence of numbers, denoted by
A very important class of discrete-time signals is obtained by sampling a continuous-time signal
IN MATLAB: command plot used to sketch the continuous time signals
IN MATLAB: command stem used to sketch the discrete time signals
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4. Plotting Time domain using Matlab
concept
A general sine wave in time domain can be represented by three parameters :
Peak amplitude (A)
Frequency (f)
Phase (φ)
s(t) = A sin(2π f t +Φ)
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5. Plotting Time domain using Matlab
To open the editor click on New -> Script

6. Plotting Time domain using Matlab
Example
Example:
Plot and stem the time domain signal
7*sin(2*pi*2000*t+pi), t=0:0.05:3
If you include “;” at the
end of each statement,
result will not be shown
immediately
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7. Run and save
After writing the code click on Run button to save the code and run it .

8. Plotting Frequency domain using Matlab
concept
Using discipline Known as Fourier analysis (any signal is made up of components at various frequencies, in which each component is a sinusoid ).
Eg. s(t) = [(4/π) x (sin(2πft) + (1/3) sin(2π(3f)t)]
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9. Plotting Frequency domain using Matlab
example
Plot each signals alone the show the frequency domain( Fourier) signal..t=0:0.01:5
s(t)=[6*sin(2pi*t+pi)+4*sin(2*pi*3t+pi)+ 2*sin(2*pi*5t+3*pi)]
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10. Networks and Communication Department

11. The End
Any Questions ?
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