Transcript Lab3 - WordPress.com

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NET 222: COMMUNICATIONS AND
NETWORKS FUNDAMENTALS
(PRACTICAL PART)
Networks and
Communication
Department
Lab 3: Matlab – Sinusoidal&Exercises
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Sinusoidal
Time & Frequency domain
continuous or discrete signals
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continuous or discrete signals
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

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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Plotting Time domain using Matlab
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
Time
Domain
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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Plotting Time domain using Matlab
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
Time
Domain
Example:

Plot and stem the time domain signal
7*sin(2*pi*2000*t+pi),
t=0:0.05:3
Matlab
Example
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Plotting Frequency domain using Matlab
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
Frequency
Domain
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)]
concept
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Plotting Frequency domain using Matlab
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Frequency
Domain
Matlab

Plot each signals alone the show the
frequency domain( Fourier) signal

s(t)=[6*sin(2pi*t+pi)+4*sin(2*pi*3t+pi)+
2*sin(2*pi*5t+3*pi)]
example
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Exercises Contents
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



Basic exercises
Arrays & Matrices
Plotting
Sinusoid Sampling
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Basic exercises
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Let vector x = [5 2 1 6]:
1.
A.
B.
Add 16 to each element
Let y = [4 1 3 5], multiply x*y
A.
Adding 16 to vector x in matlab
B.
Multiplying two vectors x and y
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Basic exercises
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Evaluate the following MATLAB expressions by your hand and
use MATLAB for checking your ans.:
2.
A.
B.
2/2*3
(6 - 2 ) / 5 + 7 ^ 2 – 1
A.
B.
Hands calculation:
2/2=1
1*3 = 3
In Matlab:
Basic exercises
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Let vector t= 2, 4, 6, 8…20:
3.
A.
Compute cos^2(t)
%Notice that vector t is a starting
form 2 and incremented by 2 till 20
% cos^2(t) is written as cos(t).^2
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Basic exercises
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Let vector t= 2, 4, 6, 8…20:
3.
B.
Exp^t(1+ cos(3t))
% exp^t is written as exp(t).
%Notice that vector t is a starting
form 2 and incremented by 2 till 20
Arrays & Matrices
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Given an array A = [ 2 4 1
1.
672
3 5 9]
provide the commands needed to:
A.
assign the first row of A to a vector called x1
%Array in matlab written as each rows
separated by ;
%assign the first row till end
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Arrays & Matrices
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Given an array A = [ 2 4 1
672
3 5 9]
provide the commands needed to:
1.
B.
assign the last 2 rows of A to an array called y
% end-1 is row before the last row
% end is the last row
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Arrays & Matrices
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Given an array A = [ 2 4 1
672
3 5 9]
provide the commands needed to:
1.
C.
compute the square-root of each element of A
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Arrays & Matrices
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Transpose the following matrices:
2.
A.
B.
A=[2 7 9 7 ; 3 1 5 6 ; 8 1 2 5]
B=[3 2 6 8]
A.
B.
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Plotting
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1.
Plot sin(x2) on the interval [-5,5].
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Plotting
three curve on the interval [0,2π] step π/100
.the curve equation
y = sin(x), y2 = sin(x-.25), y3 = sin(x2. Create
.5);
Sinusoid Sampling
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1.
Sample the sinusoid x = sin(2 pi f t), where f = 2 kHz. And
t=0:5T

Let x1 be the signal sampled at 10 kHz.
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Sinusoid Sampling
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1.
Sample the sinusoid x = sin(2 pi f t), where f = 2 kHz. And
t=0:5T

Let x2 be the signal sampled at 3 kHz
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Sinusoid Sampling
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2.
Plot frequency domain sinusoid x = sin(2 pi f t), where fs= 8000 Hz. At different
frequency tones start from 0 till 1, then multiplying the tones with 2
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The End
Any Questions ?
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