ac mat lab prog

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


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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title('carrier signal');

subplot(4,1,3);plot(t,s);

xlabel('time');


title('Amplitude modulated signal');

d=s.*c;

subplot(4,1,4);

plot(t,d);

xlabel('time');


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 demodulation.


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');


title('message signal');subplot(5,1,2);

plot(t,c);


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xlabel('time');


title('carrier signal');subplot(5,1,3);

plot(t,s1);

xlabel('time');


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');


title('demodulated signal');


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Fig: SSB SYSTEM

Result: Hence we generated singleside band (SSB) amplitudemodulation and demodulation.


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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');



subplot(4,1,2);

plot(t,c);

xlabel('time');



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subplot(4,1,3);

plot(t,s);xlabel('time');


title('DSBSC signal');

d=s.*c;

subplot(4,1,4);

plot(t,d);

xlabel('time');


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.


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');



subplot(3,1,2);

plot(t,c);

xlabel('time');




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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.


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.


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


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.

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