EC 6512 CS Lab Manual

7/26/2019 EC 6512 CS Lab Manual

1/58

UNITED INSTITUTE OF TECHNOLOGY Periyanaickenpalayam, Coimbatore- 641 020.

LABORATORY MANUAL

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

EC6512 - COMMUNICATION SYSTEM LABORATORY

NAME: ___________________ ROLL NO: __________________

SEMESTER: _______________ BATCH: ________________

REGISTER NO: _________________________

SIGNATURE OF LAB IN CHARGE HEAD OF THE DEPARTMENT

SYLLABUS


2/58

CommunicationSystem Lab

2

EC6512 COMMUNICATION SYSTEMS LABORATORY L T P C 0 0 3 2

OBJECTIVES: The student should be made to:

To isuali!e the e""ects o" samplin# and T$% To &mplement '% ( )% modulation and demodulation

To implement PC% ( $%

To implement )*+, P*+ and $P*+ schemes

To implement uali!ation al#orithms

To implement rror control codin# schemes

LIST OF E PERIMENTS:

1. *i#nal *amplin# and reconstruction

2. Time $i ision %ultiple in#

/. '% %odulator and $emodulator

4. )% %odulator and $emodulator

. Pulse Code %odulation and $emodulation

6. $elta %odulation and $emodulation

. bser ation 3simulation o" si#nal constellations o" 5P*+, P*+ and '%

7. 8ine codin# schemes

9. )*+, P*+ and $P*+ schemes 3*imulation

10. rror control codin# schemes 8inear 5lock Codes 3*imulation

11. Communication link simulation

12. uali!ation ;ero )orcin# ( 8%* al#orithms 3simulation

TOTAL: !5 PERIODS


3/58


3

LIST OF E PERIMENTS

S"NO DATE NAME OF THE E PERIMENTPAGE

NOMAR#S SIGNATURE

1 *i#nal *amplin# and reconstruction

2 Time $i ision %ultiple in#

3 '% %odulator and $emodulator

! )% %odulator and $emodulator

5 Pulse Code %odulation and $emodulation

6 $elta %odulation and $emodulation

$bser ation 3simulation o" si#nal

constellations o" 5P*+, P*+ and'%

%8ine codin# schemes

&)*+, P*+ and $P*+ schemes

3*imulation10

rror control codin# schemes 8inear5lock Codes 3*imulation


4/58


4

1" SAMPLING AND RECONSTRUCTION OF ANALOG SIGNAL

AIM:To study the si#nal samplin# and ?@ hert!is completely described by speci"ied the alues o" the si#nal o" instants o" time separated by1A2? seconds, Bhere >?@ is the hi#her "re uency content. The !ero order hold circuit is used "or

practical reconstruction. &t simply hold the alue 3n "or >T@ seconds . ere >T@ is the samplin# periodD The output o" !ero order hold is stair case si#nal. The reconstructed si#nal is thesuccession o" sinc pulses Bei#hted by 3nTs these pulses are interpolated Bith the help o" a 8P).&t is also called reconstruction "ilter or interpolation "ilter Eatural samplin# is chopper samplin#

because the Ba e"orm o" the sampled si#nal appears to be chopped o"" "rom the ori#inal si#nalBa e"orm. The top o" the samples remains constant and e ual to instantaneous alue o" 3t atstart o" samplin# "s F 1ATs

PROCEDURE:1. Connect the main plu# in to the main board. +eep the poBer sBitch in )) position.2. Put the duty cycle selector sBitch in position 0G/. 8ink 2 ! sine Ba e output to analo# input.4. Turn on the trainer.

. Turnin# on the trainer select 2 0 ! samplin# rate by de"ault.6. $isplay 2 ! sine Ba e and sampled output on t oscilloscope. This display shoBs 2 !

sine Ba e bein# sampled at 200 ! there are 10 samples "or e ery cycle o" the sine Ba e.. 8ink the sample output to the "ourth order loB pass "ilter display sample output and

output o" the "ilter in the oscilloscope. The display shoBs the reconstructed ori#inal 21! sine Ba e.

7. ?e had used samplin# "re uency #reater than tBice the ma imum input "re uency.9.


5/58


5

TABULATION

'%P8&TH$ T&% P


6/58


6

12. *o "ar Be ha e used samplin# "re uencies #reater than tBice the ma imum input"re uency. To set the n uist criteria set samplin# rate 4 ! 0G duty cycle.

1/.


7/58

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-1

0

1USER 1

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2-1

0

1USER 2

2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3-1

0

1USER 3

0 0.5 1 1.5 2 2.5 3-1

0

1TIME DIVISION MULTIPLEXING


7

Thus the si#nal samplin# and reconstruction techni ues Bas per"ormed and #raph Bas plotted.

OUTPUT (AVEFORM


8/58


8

2" TIME DIVISION MULTIPLE ING )TDM*

AIM: To study samplin# and time di ision multiple in# 3T$% usin# hardBare and %'T8'5so"tBare.

APPARATUS RE'UIRED:

1. Computer2. Matlab software ersion 7.4

THEORY:TDM:

!ime "i#ision multiple$in% &!'M( is t)e process of sen"in% more t)an one sourceinformation o#er a same c)annel in "i*erent time slot w)ic) )elps in e+cientc)annel utili,ation an" sa#es ban"wi"t).

PROCEDURE:1. pen %atlab ersion .42. pen neB "ile and enter the pro#ram and sa e it./. 'dd the path to the location o" the "ile in the system.4. Compile the pro#ram and check "or any error and debu# it.

. Eote doBn the output.

MATLAB CODING+

n1Finput3 L nter the len#th L Dn2Finput3 L nter the len#th L Dn/Finput3 L nter the len#th L DtF0:0.01:n1Dt1F1:0.01:n2Dt2F2:0.01:n/D

Fsin32MpiMt DyFsin34MpiMt1 D!Fsin36MpiMt2 D

subplot34,1,1 D plot3t, ,L#LDtitle3LH* < 1L D#rid onDsubplot34,1,2 D

plot3t1,y, LrLDtitle3LH* < 2L D


9/58


-


10/58


1

#rid onDsubplot34,1,/ D

plot3t2,! Dtitle3LH* < /L D#rid onDsubplot34,1,4 D

plot3t, ,L#L,t1,y, LrL,t2,! DT&T8 3LT&% $&=&*& E %H8T&P8 N&EJLD#rid onD

nter the len#th 1nter the len#th 2nter the len#th /

RESULT:


11/58


11

Thus the si#nal is sampled and reconstructed usin# samplin# kit and pro#ram "or T$% codin# isdone usin# %'T8'5 and the output is eri"ied.

MODEL GRAPH


12/58


12

3" AMPLITUDE MODULATION AND DEMODULATON


13/58


13

AIM:

To per"orm the amplitude modulation and demodulation a usin# '% +it.

APPARATUS RE'UIRED:1. 'mplitude modulation kit2. $*/. Probe4. Patch cord

MODULATION THEORY:%odulation is de"ined as the process by Bhich some characteristics o" a carrier si#nal is

aried in accordance Bith a modulatin# si#nal. The base band si#nal is re"erred to as themodulatin# si#nal and the output o" the modulation process is called as the modulation si#nal.

'mplitude modulation is de"ined as the process in Bhich is the amplitude o" the carrier Ba e is aried about a means alues linearly Bith the base band si#nal. The en elope o" themodulatin# Ba e has the same shape as the base band si#nal pro ided the "olloBin# tBore uirements are satis"ied

The carrier "re uency "c must be much #reater than the hi#hest "re uency components "mo" the messa#e si#nal m 3t

i.e. "c OO"m

The modulation inde must be less than unity. i" the modulation inde is #reater thanunity, the carrier Ba e becomes o er modulated.

DEMODULATION THEORY:The process o" detection pro ides a means o" reco erin# the modulatin# *i#nal "rom

modulatin# si#nal. $emodulation is the re erse process o" modulation. The detector circuit isemployed to separate the carrier Ba e and eliminate the side bands. *ince the en elope o" an '%Ba e has the same shape as the messa#e, independent o" the carrier "re uency and phase,demodulation can be accomplished by e tractin# en elope.

'n increased time constant


14/58


14

'mplitude inolts

Time period

)re uency

%essa#e si#nalCarrier si#nal

%odulated si#nal

$emodulated si#nal

PROCEDURE:

A" AMPLITUDE MODULATION


15/58


15

1. Connect the mains cord o" the trainer unit to 'C 220=, 0 ! supply.

2.*Bitch E the trainer kit. The neon lamp Bill #loB indicatin# that the unit is ready

"or operation.

/. bser e the Ba e"orms o" modulatin# si#nal and carrier si#nal in an scilloscope.

4.Hsin# patch cords, connect the modulatin# si#nal and the carrier si#nal to

>'% % $H8'T& E@.

. bser e the amplitude modulated output Ba e"orm across sockets marked

>'% HTPHT@.

B" AM DEMODULATION1.*et the amplitude o" modulatin# and carrier si#nal in 'mplitude %odulation.

2. Hsin# patch cords, connect the >'% HTPHT@ "rom the '% %odulation

to the sockets marked >'% &EPHT> in the '% $emodulation.

/.Connect the detector output to "ilter input usin# patch cords.

4.Connect the "ilter output to ampli"ier input.

.Connect the ampli"ier output to in ertin# ampli"ier input.

6. bser e the demodulated output Ba e"orm across sockets marked>$ % $ HTPHT@.

RESULT:

Thus the amplitude modulation and demodulation Bere per"ormed.

MODEL GRAPH:


16/58


16

!" FRE'UENCY MODULATION AND DEMODULATION


17/58


17

AIM:To per"orm )re uency modulation techni ue.

APPARATUS RE'UIRED:

1" )re uency modulation kit2" $*3" Probe!" Patch cord

THEORY:)re uency modulation is a process o" chan#in# the "re uency o" a carrier Ba e in

accordance Bith the sloBly aryin# base band si#nal. The main ad anta#e o" this modulation isthat it can pro ide better discrimination a#ainst noise.

PROCEDURE:

1.Connect the mains cord o" the trainer unit to 'C 220=, 0 ! supply.


"or operation.

/. bser e the %odulatin# *i#nal in an scilloscope.

4. bser e the )% *ource in the scilloscope.

.Hsin# patch cords, connect the )% *ource to sockets marked >)% &EPHT@ in

)% $etector Circuit.

6. bser e the )re uency $emodulated utput *i#nal across sockets marked

>$ % $ HTPHT@.

TABULATION:


18/58


18

'mplitude inolts

Time period

)re uency

%essa#e si#nalCarrier si#nal

%odulated si#nal

$emodulated si#nal

'UESTIONS:


19/58


1-

1.?hat Bill be the chan#es in the Ba e under )% Bhen the amplitude or "re uency o" themodulatin# si#nal is increased K2. The )% station ha e less noise Bhile recei in# the si#nal. Qusti"y your ansBer./. ?hat happens Bhen a stron#er si#nal and a Beaker si#nal both o erlap at the same "re uency

in )%K4. Eame tBo applications o" tBo Bay mobile radioK

. ?hich mathematical e pression is used to decide the side band amplitudes in a )% si#nal K

RESULT:

Thus the )% per"ormed and the modulation inde Bas "ound.

BLOC# DIAGRAM


20/58


2

5" PULSE CODE MODULATION AND DEMODULATION


21/58


21

A, :

To per"orm Pulse code %odulation and demodulation and to plot the Ba e"orm "or binarydata at di""erent "re uencies

A../ / R4 , 4 :

1. PC% kit2. $*/. Probe4. Patch cord

THEORY:

PC% is a method o" con ertin# an analo# in to di#ita si#nals . &n"ormation in a analo#"orm cannot be processes by di#ital computers so its necessary to con ert them in to di#ital PC%is term Bhich Bas "ormed durin# the de elopment o" di#ital audio transmission standards.$i#ital data can be transported robustly o er lon# distances unlike the analo# data and can beinterlea ed Bith other di#ital data sos arious combinations o" transmission channels can beused.

P 784 4:

1.Connect the mains cord o" the trainer unit to 'C 220=, 0 ! supply.


"or operation.

/. bser e the %odulatin# *i#nal in an scilloscope.

4. bser e the )% *ource in the scilloscope.

.Hsin# patch cords, connect sineBa e si#nal source to the sample ( hold circuits.

6.Connect the clock si#nal to the respecti e sta#es.

. bser e the PC% output si#nal across the sockets marked PC% HTPHTR7. Pulse mode modulated can also be obser ed by ariable $C supply

TABULATION


22/58


22

PARAMETERS AMPLITUDE IN)VOLTS*TIME PERIOD IN

) *FR'UENCY IN

)H9*

MESSAGE SIGNAL

MODULATEDSIGNAL

DEMODULATEDSIGNAL

DEMODULATION:

1. Hsin# patch cord connect the output "rom pulse code modulation to the sockets .


23/58


23

2. bser e the PC+ demodulated output si#nal across the sockets marked $ % $HTPHTR

VIVA 'UESTIONS

1. $e"ine PC%K2. ?hat are the ad anta#es o" PC%K/. ?hat are the applications o" PC% K4. ?hat are the types o" PC% si#nalK

RESULT

Thus the Pulse Code %odulation and $emodulation Bas per"ormed and output is eri"ied.

BLOC# DIAGRAM


24/58


24

DM MODULATOR AND DEMODULATOR

6" DELTA MODULATION AND DEMODULATION

AIM:


25/58


25

To per"orm the $elta %odulation and $emodulation.

APPARATUS RE'UIRED:

1. $% kit2. $*/. Probe4. Patch cord

THEORY:

$elta %odulation is a "orm o" pulse modulation Bhere a sample alue is represented as a sin#le bit. This is almost similar to di""erential PC%, as the transmitted bit is only one per sample Sustto indicate Bhether the present sample is lar#er or smaller than the pre ious one. The encodin#,decodin# and uanti!in# process become e tremely simple but this system cannot handle rapidly

aryin# samples. This increases the uanti!in# noise.

PROCEDURE:

A" DELTA MODULATION1.Connect the mains cord o" the trainer unit to 'C 220=, 0 ! supply.


"or operation.

/. bser e the Ba e"orms o" %odulatin# *i#nal Jenerator and Clock *i#nal Jenerator

in an scilloscope.

4.Hsin# patch cords, connect the modulatin# si#nal to the sockets marked >% $ *&JE'8@

in the $elta %odulation.

.Hsin# patch cords, connect the clock si#nal to the sockets marked >C8+@ in the

*i#nal


26/58


26

MODEL GRAPH

6.Connect the >$ 8T' % $ HTPHT@ in $elta %odulator to the sockets marked

>$ 8T' % $ &EPHT@ in the *i#nal


27/58


27


28/58


28

$" OBSERVATION )SIMULATION* OF SIGNAL CONSTELLATIONS OF BPS# 'PS#

AND 'AM

AIM:

To simulate 5P*+ P*+ and '% usin# %'T 8ab .

APPARATUS RE'UIRED:

1. Computer 2. %atlab so"tBare =ersion .4

PROCEDURE:

1. pen %atlab ersion .42. pen neB "ile and enter the pro#ram and sa e it./. 'dd the path to the location o" the "ile in the system.4. Compile the pro#ram and check "or any error and debu# it.

. Eote doBn the output.


29/58


2-

MATLAB CODING:

BPS# MATLAB CODE

clcDclear allD bitsF1000000DdataFrandint31,bits O0. DebnoF0:10D5


30/58


3

upsampFUsymbD!VD upsamp2Freshape3upsamp,1,3% Mbits D GPassin# the symbols "rom P*)

t WsymbFcon 3upsamp2,ps" D

G--------C 'EE 8----------- G


31/58


31

SIMULATED VS THEORITICAL BIT ERROR RATE FOR 'PS#

'PS# MATLAB CODE


32/58


32

clcclear all

bitsF1000000DdataFrandint31,bits O0. D

G---debu##in#---GdataFU1 1 1VGebnoF0:10D5


33/58


33

SIGNAL SPECTRUM FOR SIGNAL (ITH RECTANGULAR PULSE SHAPING FOR'PS#

G-------< C &=


34/58


34

r Fr 31:1:bitsA2 D rec WbitsF!eros31,bits D Gdemappin# kF1D

"or iiF1:bitsA2 rec Wbits3k F -3 si#n3 real3 r 3ii -1 A2D rec Wbits3kY1 F-3 si#n3 ima#3 r 3ii -1 A2D kFkY2D end Gsi#n3 real3 r Gsi#n3 ima#3 r Gdata Gt Wsymb Gr Wsymb

Grec Wbits G G---*&%H8'T $ 5&T


35/58


35

SIGNAL SPECTRUM FOR SIGNAL (ITH RECTANGULAR PULSE SHAPING FOR% 'AM

'AM MATLAB CODE


36/58


36

clcclear all

bitsF/000000DdataFrandint31,bits O0. D

G---debu##in#---GdataFU1 1 1VGebnoF0:10D5


37/58


37

SIMULATED VS THEORITICAL BIT ERROR RATE FOR %- 'AM

&3k F-1D 3k F-1D


38/58


38

kFkY1D elsei" 3data3i:iY2 FFU1 1 1V

&3k F-/D

3k F-1D kFkY1D end endsymbF&YSM DGreal3symbGima#3symb G----)ilter ps"Fones31,1 D sFsum3ps".X2 D ebF sA/D

ebF2D G---- %Flen#th3ps" D"or iF1:len#th3ebno G insertin# !eros betBeen the bits

G B.r.t number o" coe""icients o"G P*) to pass the bit stream "rom the P*)

!F!eros3%-1,bitsA/ D upsampFUsymbD!VD upsamp2Freshape3upsamp,1,3% MbitsA/ D GPassin# the symbols "rom P*)

Gt WsymbFcon 3real3upsamp2 ,ps" YSMcon 3ima#3upsamp2 ,ps" D t WsymbFcon 3upsamp2,ps" D G--------C 'EE 8----------- G


39/58


3-

"or nF1:bitsA/ &Freal3r 3n D


40/58


4

Fima#3r 3n D i" 3& O 0 (( 3& Z 2 (( 3 O 0 rec Wbits3k:kY2 FU0 0 0VD elsei" 3& O 0 (( 3& Z 2 (( 3 Z 0

rec Wbits3k:kY2 FU1 0 0VD elsei" 3& O 2 (( 3 O0 rec Wbits3k:kY2 FU0 0 1VD elsei" 3& O 2 (( 3 Z 0 rec Wbits3k:kY2 FU1 0 1VD elsei" 3& Z 0 (( 3& O -2 (( 3 O 0 rec Wbits3k:kY2 FU0 1 0VD elsei" 3& Z 0 (( 3& O -2 (( 3 Z 0 rec Wbits3k:kY2 FU1 1 0VD elsei" 3& Z -2 (( 3 O 0 rec Wbits3k:kY2 FU0 1 1VD

elsei" 3& Z -2 (( 3 Z 0 rec Wbits3k:kY2 FU1 1 1VD end kFkY/D end t WsymbD r WsymbD dataD rec WbitsD G G---*&%H8'T $ 5&T


41/58


41

semilo#y3ebno,5


42/58


42

Gebno2F310.X3ebnoA10 DGthrF3 A12 .Mer"c3s rt3310.X3ebnoA10 .A2 Dsemilo#y3ebno,thr, Lr -LD

label3L bAEo 3d5 L

ylabel3L5it rror rateLtitle3L*imulated =s Theoritical 5it rror


43/58


43

MODEL GRAPH

%" LINE CODING AND DECODING TECHNI'UES


44/58


44

AIM :To study di""erent line codin# techni ues.

APPARATUS RE'UIRED :1. Communication trainer kit

2. Patch cords./. $* AC

Documents

EC 6512 CS Lab Manual