lab manual ece321

5/21/2018 Lab Manual ECE321

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LABORATORY MANUAL

ECE321

COMMUNICATION SYSTEM

LABORATORY


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Table of Content

SerialNo.

List of Experiments PageNo

1. To obtain time domain AM envelope in CRO and recovering themessage signal using envelope detector circuit 2-5

2. To obtain FM time domain waveform in CRO and to calculatemodulation index and frequency deviation for FM

6-8

3. To obtain time domain PAM signal in CRO and to calculate thediscrete amplitude levels of modulated carrier pulses.

9-12

4. To obtain a Delta modulated signal and calculate slopeoverload and granular noise using Matlab

13-15

5. To obtain PCM signal with proper analysis of sampling,quantization and encoding using Matlab

16-18

6. To obtain Unipolar, polar and bipolar line coded signal for RZand NRZ techniques using Matlab

19-21

7. To obtain Binary ASK modulated signal and to calculate thebandwidth

22-23

8. To obtain Binary FSK modulated signal and to calculate thebandwidth using Matlab

24-25

9. To obtain BPSK signal using Matlab and to calculate thebandwidth

26-27

10. To obtain TDM signal and to calculate the data rate of themultiplexed signal using Matlab

28-30


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Experiment1

Aim: To obtain time domain AM envelope in CRO and recovering the message signal using

envelope detector circuit

Equipments required:One IC BC 107BP, 10k, 20kohm resistor, three 0.01F capacitor,

CRO(20 Mhz),Function generator(1Mhz), connecting wires and probes.

Learning objectives:

1. To obtain AM envelope in CRO and to calculate modulation index.

2. To recover message signal using envelope detector.

Circuit diagram:

Fig1. AM envelope genaration

Fig2. Envelope detector


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Outline of the procedure:

1. Connect the circuit as per Fig1.

2. Apply fixed frequency carrier signal to carrier input terminals.

3. Apply modulating signal from function generator of 0.8VP-P of 1 KHz.

4. Note down and trace the modulated signal envelop on the CRO screen.

5. Find the modulation index by measuring Vmax and Vmin from the modulated(detected/ traced) envelope.


7. Feed the AM wave to the demodulator circuit and observe the output.

8. Note down frequency and amplitude of the demodulated output waveform.

9. Draw the demodulated wave form for modulation index=1.

Observation:


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Error Analysis:Calculate Modulation index using mathematical formula mc = (Vm/Vc)x100%ERROR = [(mmc)/ mc] x 100%

Learning Outcomes:To be written by students in 50-70 words.

Cautions:

1. Check the connections properly before applying the power supply.

2. Need to be careful and serious when interfacing the connections between

breadboard and power supply.


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Date of Performance Worksheet of the student Registration Number

Aim:

Observation:

Result and Discussion:

Graph/Plot:

Error Analysis:

Learning Outcomes (what I have learnt):

S.No. Parameter Marks obtained Max. Marks

1. Understanding of the studentabout the procedure/apparatus.

20

2. Observations and analysisincluding learning outcomes

20

3. Completion of experiment,Discipline and Cleanliness

10

Signature of Faculty Total marksobtained


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Experiment 2

Aim: To obtain FM time domain waveform in CRO and to calculate modulation index and

frequency deviation for FM

Equipments required:IC LM 2206,10k, two 100k, three 4.7k, 220ohm resistor values,

22F,1F, 10F, 0.01F capacitor values, CRO(20 Mhz), Function generator(1Mhz),connecting wires and probes.


1. To obtain FM in CRO and to calculate modulation index.

Circuit diagram:

Fig3. FM generation



2. Apply the modulating signal of 100HZ with 3Vp-p.

3. Trace the modulated wave on the C.R.O & plot the same on graph.

4. Find the modulation index by measuring minimum and maximum frequency

deviations from the carrier frequency using the CRO.

5. M = S/f = maximum Frequency deviation /modulating signal frequency

6. Repeat the steps 3& 4 by changing the amplitude and /or frequency of the modulatingSignal


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Observation:

Error Analysis:

Student need to calculate error in calculation as per observation table.


Cautions:





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Aim:

Observation:


Graph/Plot:

Error Analysis:




20


20


10



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Experiment 3

Aim: To obtain time domain PAM signal in CRO and to calculate the discrete amplitude

levels of modulated carrier pulses.

Equipments required:


1. To obtain PAM in CRO and to calculate discrete amplitudes.

Circuit diagram:

Fig4. PAM generation


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Fig5. PAM demodulation


1. Connect the circuit as per Fig 4.

2. Set the modulating frequency to 1KHz and sampling frequency to 12KHz

3. Observe the o/p on CRO i.e. PAM wave.

4. Measure the levels of Emax & Emin.

5. Feed the modulated wave to the low pass filter as in Fig 5.

6. The output observed on CRO will be the demodulated wave.

7. Note down the amplitude (p-p) and time period of the demodulated wave. Vary the

amplitude and frequency of modulating signal.

8. Observe and note down the changes in output.

9. Plot the wave forms on graph sheet.

Observation:


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Cautions:





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Aim:

Observation:


Graph/Plot:

Error Analysis:




20


20


10



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Experiment 4

Aim: To obtain a Delta modulated signal and calculate slope overload and granular noise

using Matlab

Equipments Required:Computer, MatLab-7.5 Software

Learning Objectives:

1. To implement the MatLab code for delta modulation2. To calculate condition for avoid slop overload error.

Mat Lab Code:A general guidelines of code has been given below but student need todevelop the complete program as per the learning objectives.

% DELTA MODULATiONfigure(1);a=2;t=0:2*pi/50:2*pi;x=a*sin(t);

l=length(x);plot(x,'r');delta=0.2;hold onxn=0;for i=1:l;if x(i)>xn(i)d(i)=1;xn(i+1)=xn(i)+delta;elsed(i)=0; xn(i+1)=xn(i)-delta;

endendstairs(xn)hold onfor i=1:dif d(i)>xn(i)d(i)=0;xn(i+1)=xn(i)-delta;elsed(i)=1;xn(i+1)=xn(i)+delta;

endendplot(xn,'c');legend('Analog signal','Delta modulation','Demodulation')title('DELTA MODULATION / DEMODULATION ')

Outline of the Procedure:


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1. Open a new M-File or Script window in MatLab.2. Type the MatLab code and execute it.3. Do necessary modifications in code as per learning objectives.4. View the results in command window / figure window.5. Plot the results.



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Aim:

Observation:


Graph/Plot:

Error Analysis:




20


20


10



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Experiment 5

Aim: To obtain PCM signal with proper analysis of sampling, quantization and encoding

using Matlab

Equipments Required:Computer, MatLab-7.5 Software.

Learning Objective:1. To implement the MatLab code for pulse code modulation.

MatLab Code:A general guidelines of code has been given below but student need to

develop the complete program as per the learning objectives.

%Pulse code modulationA=2;fc=3;fs=20;n=3;

t=0:1/(100*fc):1;x=A*sin(2*pi*fc*t);ts=0:1/fs:1;xs=A*sin(2*pi*fc*ts);x1=xs+A;x1=x1/(2*A);L=(-1+2^n);x1=L*x1;xq=round(x1);r=xq/L;r=2*A*r;

r=r-A;y=[];for i=1:length(xq);d=dec2bin(xq(i),n);y=[y double(d)-48];endMSE=sum((xs-r).^2)/length(x);Bitrate=n*fs;Stepsize=2*A/L;QNoise=((Stepsize)^2)/12;subplot(3,1,1);

plot(t,x,'linewidth',2)title('step 1')ylabel('y axis')xlabel('t(in sec)')hold onstem(ts,xs,'r','linewidth',2)hold offlegend('analog signal',' sampling');subplot(3,1,2);


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stem(ts,x1,'linewidth',2)title('step 2')ylabel('Y axis')hold onstem(ts,xq,'r','linewidth',2)plot(ts,xq,'--r')plot(t,(x+A)*L/(2*A), '--b')gridhold offlegend('Quantization','sampling');subplot(3,1,3);stairs([y y(length(y))],'linewidth',2)title('PCM')ylabel('Y axis')xlabel('bits')axis([0 length(y) -2 2])grid


1. Open a new M-File or Script window in MatLab. 2. Type the MatLab code and execute it.3. View the results in command window / figure window. 4. Plot the Results.



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Aim:

Observation:


Graph/Plot:

Error Analysis:




20


20


10

Signature of Faculty Total marks

obtained


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Experiment 6

Aim: To obtain Unipolar, polar and bipolar line coded signal for RZ and NRZ techniques

using Matlab

Equipments Required: MatLab-7.5 Software.


1. To implement the MatLab code for various line coding techniques.

MatLab Code:A general guidelines of code has been given below but student need todevelop the complete program as per the learning objectives.

%Pulse data coding techniquesa=[1 0 0 1 1]; U=a;n=length(a);U(n+1)=U(n);%POLARP=a;for k=1:n;

if a(k)==0P(k)=-1;endP(n+1)=P(n);end%BipolarB=a;f = -1;for k=1:n;if B(k)==1;if f==-1;

B(k)=1; f=1;elseB(k)=-1; f=-1;endendB(n+1)=B(n);end%MarkM(1)=1;for k=1:n;M(k+1)=xor(M(k), a(k));

end%SpaceS(1)=1;for k=1:nS(k+1)=not(xor(S(k), a(k)));end%Plotting Wavessubplot(5, 1, 1);stairs(U)


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axis([1 n+2 -2 2])title('Unipolar NRZ')grid onsubplot(5, 1, 2);stairs(P)axis([1 n+2 -2 2])title('Polar NRZ')grid onsubplot(5, 1, 3);stairs(B)axis([1 n+2 -2 2])title('Bipolar NRZ')grid onsubplot(5, 1, 4);stairs(M)axis([1 n+2 -2 2])title('NRZ-Mark')grid onsubplot(5, 1, 5);stairs(S)axis([1 n+2 -2 2])title('NRZ-Space')grid on


1. Open a new M-File or Script window in MatLab.2. Type the MatLab code and execute it.3. View the results in command window / figure window.4. Plot the results.

Learning Outcomes:To be written by students in 50-70 words


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Aim:

Observation:


Graph/Plot:

Error Analysis:




20


20


10



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Experiment 7:

Aim: To obtain Binary ASK modulated signal and to calculate the bandwidth



1. To implement the MatLab code for amplitude shift keying.


%Amplitude shift keyingclc;clear all;close all;s=[1 0 1 1 1 0];f1=10;

a=length(s);for i=1:af=f1*s(1,i);for t=(i-1)*100+1:i*100x(t)=sin(2*pi*f*t/1000)endendplot(x)xlabel('time in secs')ylabel('amplitude in volts')title('ASK')

grid on


1. Open a new M-File or Script window in MatLab. 2. Type the MatLab code and execute it.3. View the results in command window / figure window. 4. Plot the results.

Learning Outcomes: To be written by students in 50-70 words.


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Aim:

Observation:


Graph/Plot:

Error Analysis:




20


20


10



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Experiment 8

Aim:To obtain Binary FSK modulated signal and to calculate the bandwidth using Matlab



1. To implement the MatLab code for frequency shift keying.



%Frequency shift keying

clc;clear all;close all;s=[1 0 1 0];f1=10;

f2=50;a=length (s);for i=1:aif s(1,i)==1freq=f1*s(1,i);for t= (i-1)*100+1:i*100x(t)= sin(2*pi*freq*t/1000);endelseif s(1,i)==0b=(2*s(1,i))+1;freq=f2*b;

for t=(i-1)*100+1:i*100x(t)= sin(2*pi*freq*t/1000);endendendplot(x);xlabel('title in secs');ylabel('amplitude in volts')title ('FSK')grid on


1. Open a new M-File or Script window in MatLab.2. Type the MatLab code and execute it.3. View the results in command window / figure window.4. Plot the results.

Learning Outcomes: To be written by students in 50-70 words.


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Aim:

Observation:


Graph/Plot:

Error Analysis:




20


20


10



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Experiment 9

Aim: To obtain BPSK signal using Matlab and to calculate the bandwidth

Equipments Required: Computer, MatLab-7.5 Software.


1. To implement the MatLab code for phase shift keying.


%Phase shift keyingclc;clear all;close all;s=[1 0 1 0];f1=10;a=length(s);for i=1:a

if s(1,i)==1freq=f1*s(1,i);for t= (i-1)*100+1:i*100x(t)= sin(2*pi*freq*t/1000);endelseif s(1,i)==0b=(2*s(1,i))+1;freq=f1*b;for t=(i-1)*100+1:i*100x(t)= sin((2*pi*freq*t/1000)+pi);end

endendplot(x);xlabel('title in secs');ylabel('amplitude in volts')title ('PSK')grid on


1. Open a new M-File or Script window in MatLab.2. Type the MatLab code and execute it.

3. View the results in command window / figure window.4. Plot the results.



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Aim:

Observation:


Graph/Plot:

Error Analysis:




20


20


10



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Experiment 10

Aim:To obtain TDM signal and to calculate the data rate of the multiplexed signal using

Matlab



1. To implement the MatLab code for time division multiplexing



%Time division multiplexingfs=10000;t=0:1/fs:1.5;x1=sawtooth(2*pi*50*t);

x2=square(2*pi*50*t);x3=sin(2*pi*50*t);subplot(2,2,1),plot(t,x1),axis([0 0.2 -1.2 1.2]);xlabel('time(sec)');ylabel('amplitude');title('sawtooth periodic wave');subplot(2,2,2),plot(t,x2),axis([0 0.2 -1.2 1.2]);xlabel('time(sec)');ylabel('amplitude');title('square wave');subplot(2,2,3),plot(t,x3),axis([0 0.2 -1.2 1.2]);

xlabel('time(sec)');ylabel('amplitude');title('sin wave');l1=length(x1);l2=length(x2);l3=length(x3);for i=1:l1x(1,i)=x1(i);x(2,i)=x2(i);x(3,i)=x3(i);end

tdmx=reshape(x,1,3*l1);figure;plot(tdmx);dmx=reshape(tdmx,3,l1);for i=1:l1x4(i)=dmx(1,i);x5(i)=dmx(2,i);x6(i)=dmx(3,i);end


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figure;subplot(2,2,1),plot(x4);axis([0 1000 -1 1]);xlabel('time(sec)');ylabel('amplitude');title('recovered sawtooth periodic wave');subplot(2,2,2),plot(x5);axis([0 1000 -1 1]);xlabel('time(sec)');ylabel('amplitude');title('recovered square wave');subplot(2,2,3),plot(x6);axis([0 1000 -1 1]);xlabel('time(sec)');ylabel('amplitude');title('recovered sin wave');


1. Open a new M-File or Script window in MatLab.2. Type the MatLab code and execute it.3. View the results in command window / figure window.4. Plot the results



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Aim:

Observation:


Graph/Plot:

Error Analysis:




20


20


10


lab manual ece321

Documents

modulated signal

themessage signal

pcm signal

modulating signal

bpsk signal

tdm signal

time domain pam signal

fixed frequency carrier