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7/29/2019 AC MAT LAB PROG
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INTRODUCTION TO MATLAB.
1. GENERATION OF BASIC SIGNALS USING MATLAB
AIM : To generate basic signals like
unit impulse, unit step, unit ramp
signal and Exponential signals.
Requirements : Computer with
MATLAB software
% (a). Program for the generation of
UNIT impulse signal
clc; close all; clear all;f=-2:1:2;
y=[zeros(1,2),ones(1,1),zeros(1,2)]
figure(1)
subplot(2,2,1);
stem(f,y);
title('unit impulse');
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% (b). Program for the generation of
UNIT step signal
n=input('enter the n value');
f=0:1:n-1;
y=ones(1,n);
figure(1)
subplot(2,2,2);
stem(f,y);
title('unit step');
% (c).Program for the generation ofunit RAMP signal
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n=input('enter the n value');
f=0:n;
y=0:n;figure(1)
subplot(2,2,3);
stem(f,f);
title('unit ramp');
% (d).Program for the generation of
Exponential signal
n=input('the length of i/p sequency');
f=0:n
a=input('enter the a value');y=exp(a*f);
figure(1)
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subplot(2,2,4);
stem(f,y);
title('unit exponential')
OUTPUT:
y = 0 0 1 0 0
Enter the n value 6
Enter the n value 7
The length of i/p value 5
f = 0 1 2 3 4 5 6
Enter the a value 2
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FIG: Basic signals like unit impulse,
unit step, unit ramp signal and
Exponential signals
Result: Hence we generate basicsignals like unit impulse, unit step,
unit ramp signal and Exponential
signals.
-2 -1 0 1 20
0.2
0.4
0.6
0.8
1unit impulse
0 2 4 60
0.2
0.4
0.6
0.8
1unit step
0 2 4 60
2
4
6
unit ramp
0 2 4 60
1
2
3
4
x-axis
y-axis
unit exponential
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2. AMPLITUDE MODULATION &
DEMODULATION
AIM: To generate the amplitude
modulated signal and also calculate
the modulation index
Requirements : Computer with
MATLAB software.
Program: for the generation of
amplitude modulated signal.
%amplitude modulation
clc;
clear all;
close all;
f=500;
fc=5000;
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fs=8*fc;
ts=1/fs;
t=0:ts:8/f;m=cos(2*pi*f*t);
c=cos(2*pi*fc*t);
s=c+m.*c;
s1=s.*c;
subplot(4,1,1);
plot(t,m);
xlabel('time');
ylabel('magnitude');
title('message signal');
subplot(4,1,2);
plot(t,c);
xlabel('time');
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ylabel('magnitude');
title('carrier signal');
subplot(4,1,3);plot(t,s);
xlabel('time');
ylabel('magnitude');
title('Amplitude modulated signal');
d=s.*c;
subplot(4,1,4);
plot(t,d);
xlabel('time');
ylabel('magnitude');
title('demoduated signal')
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Fig: Amplitude Modulation
Result: Hence we generate the
amplitude modulated signal and
acalculated the modulation index
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3. SINGLE SIDEBAND SYSTEM
AIM: To study the generation ofsingle side band (SSB) amplitudemodulation and de- modulation.
Requirements : Computer with
MATLAB software.
Program:
%single side band system
clc;clear all;
close all;
Ac=1;
f=500;
fc=5000;
fs=8*fc;
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ts=1/fs;
t=0:ts:8/f;
m=cos(2*pi*f*t);c=cos(2*pi*fc*t);
s1=Ac/2*(m.*c-
hilbert(m).*sin(2*pi*fc*t));
s2=Ac/2*(m.*c+hilbert(m).*sin(2*pi*fc
*t));
subplot(5,1,1);
plot(t,m);
xlabel('time');
ylabel('magnitude');
title('message signal');subplot(5,1,2);
plot(t,c);
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xlabel('time');
ylabel('magnitude');
title('carrier signal');subplot(5,1,3);
plot(t,s1);
xlabel('time');
ylabel('magnitude');
title('SSB with Upper sideband
signal');
d=s1.*c;
subplot(5,1,4);
plot(t,s2);
xlabel('time');ylabel('magnitude');
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title('SSB with lowerside band
signal');
subplot(5,1,5);
plot(t,d);
xlabel('time');
ylabel('magnitude');
title('demodulated signal');
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Fig: SSB SYSTEM
Result: Hence we generated singleside band (SSB) amplitudemodulation and de- modulation.
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4.DOUBLE SIDE BAND SYSTEM
AIM: To obtain the outputcharacteristics of a Double side
band- Suppressed carrier AM
modulation and demodulation
Requirements : Computer withMATLAB software.
Program:
%double side band suppressed
carrier
clc;
clear all;
close all;
f=500;
fc=5000;
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fs=8*fc;
ts=1/fs;
t=0:ts:8/f;m=cos(2*pi*f*t);
c=cos(2*pi*fc*t);
s=m.*c;
subplot(4,1,1);
plot(t,m);
xlabel('time');
ylabel('magnitude');
title('message signal');
subplot(4,1,2);
plot(t,c);
xlabel('time');
ylabel('magnitude');
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title('carrier signal');
subplot(4,1,3);
plot(t,s);xlabel('time');
ylabel('magnitude');
title('DSBSC signal');
d=s.*c;
subplot(4,1,4);
plot(t,d);
xlabel('time');
ylabel('magnitude');
title('demodulated signal');
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Fig: DSB SYSTEM
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Result: Hence we obtained the
output characteristics of a Double
side band- Suppressed carrier AM
modulation and demodulation
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5.FREQUENCY MODULATION
Aim: To generate a frequencymodulation and demodulation signal
using Matlab Source.
Requirements : Computer with
MATLAB software
Program:
%frequency mopdulation
clc;clear all;
close all;
ac=5;
f=500;
fc=5000;
fs=8*fc;
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ts=1/fs;
t=0:ts:8/f;
m=cos(2*pi*f*t);c=cos(2*pi*fc*t);
s=ac*cos(2*pi*fc*t+5*sin(2*pi*f*t));
subplot(3,1,1);
plot(t,m);
xlabel('time');
ylabel('magnitude');
title('message signal');
subplot(3,1,2);
plot(t,c);
xlabel('time');
ylabel('magnitude');
title('carrier signal');
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subplot(3,1,3);
plot(t,s);
xlabel('time');ylabel('magnitude');
title('FM signal');
Fig: FREQUENCY MODULATION &DE MODULATION
Result: Hence we generate a
frequency modulation and
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demodulation signal using Matlab
Source.
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6. PULSE WIDTH MODULATION
AIM: To construct pulse widthmodulation circuit and observe
modulation and demodulation.
Requirements : Computer with
MATLAB software.
Program:
%pulse width modulation
clc;clear all;
close all;
fc=1000;
fs=4*fc;
ts=1/fs;
f=200;
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t=0:ts:5/f;
x=.4*sin(2*pi*f*t)+.5;
s=modulate(x,fc,fs,'pwm');subplot(3,1,1);
plot(x);
subplot(3,1,2);
plot(s);
d=demod(s,fc,fs,'pwm');
subplot(3,1,3);
plot(d);
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Fig: PULSE WIDTH
MODULATION
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Result: Hence we constructed pulse
width modulation circuit and
observed modulation and
demodulation.
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7. PULSE AMPLITUDE
MODUATION
AIM: To generate a Pulse amplitude
modulated signal and also
demodulate the original signal.
Requirements : Computer with
MATLAB software.
Program:
%pulse amplitude modulation
clc;
clear all;
close all;
f=500;
fs=12*f;
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ts=1/fs;
t=0:ts:5/f;
x=0.4*cos(2*pi*f*t)+.5;c=square(2*pi*f*t,0.5);
subplot(2,1,1);
plot(x);
subplot(2,1,2);
s=x.*c;
stem(abs(s));
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Fig: Pulse Amplitude
Modulation
Result: Hence we generate a Pulseamplitude modulated signal and also
demodulate the original signal.
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8. PULSE POSITION MODULATION
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AIM: To generate a Pulse position
modulated/demodulated signal using
Matlab source
Requirements : Computer with
MATLAB software.
Program:
%pulse position mosulation
clc;
clear all;
close all;fc=1000;
fs=4*fc;
ts=1/fs;
f=200;
t=0:ts:5/f;
x=.4*sin(2*pi*f*t)+.5;
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s=modulate(x,fc,fs,'ppm',0.6);
subplot(3,1,1);
plot(x);subplot(3,1,2);
plot(s);
d=demod(s,fc,fs,'ppm',0.6);
subplot(3,1,3);
plot(d);
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Fig: PULSE POSITION
MODUALTION
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Result: Hence we generated a Pulse
position modulated/demodulated
signal using Matlab source.
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9. SAMPLING THEOREM
AIM: To sample the given inputsignal at different sampling rates and
reconstruct the original signal by
passing through a low pass filter.
Requirements : Computer withMATLAB software.
Program:
% sampling theorem
clc;
clear all;
close all;
fm=100;
fs=600;
ts=1/fs;
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t=0:ts:10/fm;
x=sin(2*pi*fm*t);
subplot(4,1,1);stem(x);
fx=fft(x);
xr=ifft(fx);
subplot(4,1,2);
stem(xr);
fm2=400;
x2=sin(2*pi*fm2*t);
subplot(4,1,3);
stem(t,x2);
fx1=fft(x2);
xr1=ifft(fx1);
subplot(4,1,4);
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stem(xr1);
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Fig: SAMPLING THEOREM
RESULT: Hence sampling theorem is verified.