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PCM

Worked by :

Majid Mohammed AlZariey 2390/2012

Mahmoud Nasooh AlQousi 460 /2012

Supervised by:

Dr A!dulsalam " Al#holidi

Contents

Co$%e$%s 1&ha% mi'h% PCM re(er %o)) 2De*$i%io$ +

Sanaa University

Faculty of Engineering

Electrical Department

Forth year

Signal rocessing

http://www.researchgate.net/profile/Abdulsalam_Alkholidihttp://www.researchgate.net/profile/Abdulsalam_Alkholidi

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,is%ory o( PCM 6-he .ord ulse 13Modula%io$ 13A$'le Modula%io$ 14Amli%ude Modula%io$ 1Pulse Modula%io$ 19

Demodula%io$ 2A$alo' %o Di'i%al Co$ersio$ 2PCM Parame%ers 34PCM -yes 3+-he &A 5ile 5orma% 3Alia%io$s 37e(ere$es 39

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What might C! refer to""rocess Control !onitor

ersonal Call

!anager #telephones$

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rocess Control !anagement

ersonal Computer !aga%ine

o&er Control !odule

lease Call !e

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ulse Code

!odulation

De'nition

(n )rief* What (s C!"Pulse8ode modula%io$ PCM: is a da%a %ra$smissio$ sheme .ell8sui%ed %o

%ra$smi%%i$' !i$ary da%a ;i$ary da%a is a se$ PCM

%hese o$es a$d =eroes are %ra$sla%ed i$%o ulses o( %ra$smi%%ed e$er'y A ulse

.i%h a osi%ie amli%ude orreso$ds %o a !i$ary o$e? .hile a $e'a%ie

amli%ude ulse orreso$ds %o a =ero -here are seeral ada$%a'es %o usi$'

PCM %o %ra$smi% da%a

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>$ %he di'i%al domai$? C!ulse Code !odula%io$: is %he mos% s%rai'h%(or.ar

meha$ism %o s%ore audio -he a$alo' audio is samled i$ aorda$e .i%h %he

+y,uest%heorem a$d %he i$diidual samles are s%ored se

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In 1"#-, +aul M .ainey of /estern 0lectric

patented a facsimile machinewhich transmitted

its signal using 5bit +M, encoded by an opto

mechanical analogtodigital converter 2he machine d

not go into production

>$ 193? Ale 7eees ame u .i%h %he idea o

Pulse Code Modula%io$ PCM: A% %he %ime? (e.? i( a$y? %oo# $o%ie o( 7eees

deelome$% e$ 7eees .as (ored %o a!a$do$ his i$e$%io$ u$a!le %o see

ho. i% ould !e imleme$%ed .i%h %he %eh$olo'y o( %he day >$ 196+? some 2years la%er? %he 5ra$#li$ >$s%i%u%e a.arded Ale 7eees %he E%uar% ;alla$%i$e

Medal (or his io$eeri$' .or# o$ PCM Ba!eli$' i% a Fmajor ommu$ia%io$s

i$e$%io$G? %he 5ra$#li$ i$s%i%u%es ress release remi$ded %he u!li %ha% PCM

had made i% ossi!le (or %he Mari$er > saera(% %o %ra$smi% i%s .o$der(ul

ima'es o( Mars !a# %o ar%h ;u% i$ 196+? %he %rue o%e$%ial o( PCM .as s%ill

u$%aed -oday? o$ %he see$%y8*(%h a$$iersary o( 7eees idea? PCM has

!eome a$ i$dise$sa!le eleme$% i$ our moder$ ommu$ia%io$s

i$(ras%ru%ure a$d a (u$dame$%al e$a!ler o( moder$ oular ul%ure 5or

eHamle? PCM has ery drama%ially %ra$s(ormed %he .ay .e reord? dis%ri!u%ea$d lis%e$ %o musi

.ong Distance /elephony and +oise

Ale 7eees? li#e o%her e$'i$eers .or#i$' i$ %eleho$y? 'raled .i%h %he

ro!lem o( %he addi%ie $a%ure o( $oise .he$ a si'$al u$der.e$% mul%ile

amli*a%io$s alo$' a lo$' dis%a$e li$e -he deelome$% o( %eleho$y .as a

remar#a!le ada$e oer %ele'rahy !u% i% also i$%rodued a $e. halle$'e

,o. .as o$e %o %ra$smi% a$ a$alo' si'$al oer lo$' dis%a$es) Bee De 5ores%

i$e$%io$ o( %he %riode auum %u!e i$ 1906? .hih he alled %he Audio$? $o%

o$ly heralded %he !ir%h o( ele%ro$is a$d %he rise o( %he radio !roadas%

%eh$olo'y? i% also roided %eleho$y .i%h a$ imor%a$% %ool %o eHa$d %he

ra$'e o( lo$' dis%a$e allsI a$ amli*a%io$ deie ;u% eah %ime %he

%eleho$e si'$al .as amli*ed? more $oise .ould !e i$%rodued ;eause o(

%he do%8dash e$odi$'? %ele'rahy did $o% suJer (rom %he same ro!lem A

%ele'rah reea%er ould easily relia%e a .ea# do% or dash i$%o a (resh o$e

http://en.wikipedia.org/wiki/Facsimile_machinehttp://en.wikipedia.org/wiki/Facsimile_machine

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.i%hou% i$%rodui$' a$y $oise >$ 193? 7eees had o$luded %ha% %he !es%

.ay %o oerome %he $oise issue i$ lo$' dis%a$e %eleho$y .as %o %ra$smi% a

di'i%i=ed ersio$ o( %he a$alo' oie si'$al

Ale 7eees .as !or$ o$ 10 Marh 1902? i$ 7edhill? Eurrey? K 7eeess

(a%her? d.ard Ayears% 7eees? had a dis%i$'uished areer as a 'eo'raher ,e

.as $o%ed au%hor o$ ar%o'rahy a$d %he 7oyal "eo'rahial Eoie%ys

Eureyor >$ 191? Ale 7eees .e$% %o >merial Colle'e? Bo$do$? %o s%udy

e$'i$eeri$' A(%er 'radua%i$' i$ 1921? he did os%'radua%e s%udy a% >merial

Colle'e >$ 1923? 7eees joi$ed %he Bo$do$ Ba!ora%ory o( >$%er$a%io$al &es%er

le%ri? a leadi$' ma$u(a%urer o( radio a$d %eleommu$ia%io$s e$ 192+? a(%er his *rm had !ee$ %a#e$ oer !y >$%er$a%io$al -eleho$e a$d

-ele'rah >-L-:? 7eees .e$% %o .or# a% >-L-s la!ora%ory i$ Paris >% .as %her

%ha% 7eees ame u? i$ 193? .i%h %he idea o( usi$' a !i$ary rerese$%a%io$ o

sou$d %o oerome %he $oise issue i$ lo$' dis%a$e a$alo' %eleho$e

%ra$smissio$s >% a se$se i% .as a re%ur$ %o %he ro!us%$ess o( %ele'rahy

Nearly see$%ee$ years earlier? i$ 1921? Paul M 7ai$ey? (rom &es%er$ le%ri?had *led a a%e$% (or a mahi$e %ha% .ould se$d (aHes ia %ele'rahy usi$' a

PCM8li#e %eh$i% %oo# *e years (or %he

a%e$% %o !e 'ra$%ed Perhas %he a%e$% oe had diul%y .rai$' i%s mi$d

arou$d %he idea Bi%%le is #$o.$ as %o .he%her &es%er$ le%ri %oo# %he idea

seriously a$d %ried %o rodue a .or#i$' ro%o%ye 7eees #$e. $o%hi$' o(

7ai$eys PCM %eh$i

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-he 5irs% Dislosure o( PCMI Paul M 7ai$ey? O5asimile -ele'rah Eys%em?O KE

Pa%e$% 1?60?+2 5iled 20 uly 1921>ssued 30 Noem!er 1926

>$ 193? a(%er o!%ai$i$' a 5re$h a%e$% (or his idea? he *led (or a KE a%e$% i1939? .hih .as %he$ 'ra$%ed i$ 1942 ,is a%e$%s hara%erless %i%le? Fle%r

Ei'$ali$' Eys%em?G s%ood i$ shar o$%ras% %o %he 'rea% imor% o( %he a%e$%s

o$%e$%s Ma$y years la%er? 7eees realled %ha%? (rom %he !e'i$$i$'? he

Freali=ed %ha% i% ould !e %he mos% o.er(ul %ool so (ar a'ai$s% %he eJe%s o(

i$%er(ere$e o$ seeh eseially o$ lo$' rou%es .i%h ma$y re'e$era%ie

reea%ers? si$e %hese deies ould easily !e desi'$ed a$d saed so as %o

ma#e %he $oise $early $o$umula%ieG A$d ye% 7eees .al#ed a.ay (rom %his

.or# ,e reali=ed %ha% %he PCM .as a$ idea ahead o( i%s %ime -he s%a%e o(

ele%ro$is a% %he ou%!rea# o( && >> .as $o% u %o %he %as# o( ma#i$' PCM aia!le ommerial solu%io$ (or %eleho$y -ime .ould !e $eeded (or di'i%al

ele%ro$i hard.are %o a%h u %o %he dema$ds re

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mili%ary oers li#e "e$eral "eor'e Marshal did $o% %rus% A83 %o seurely

%ra$smi% %he mos% se$si%ie o( i$(orma%io$ ery early o$ i$ %he .ar? %he KE

Army as#ed ;ell Ba!s %o ome u .i%h a $e. .ay o( seuri$' oie

ommu$ia%io$s >% soo$ !eame aare$% %ha% di'i%i=i$' %he a$alo' oie

si'$al .ould allo. o$e %o aly yheri$' %eh$i"EABR %ermi$al 1943:

Duri$' %he 19484 eriod? i$ $umerous ar%iles? %he ;ell Ba!s .or# o$ PCM

*$ally !eame u!li ,E ;la# a$d dso$? .ho had !ee$ #ey eole i$

;ells seeh e$ry%io$ eJor%s? u!lished %heir aou$% i$ %he A>

-ra$sa%io$s -hey a$$ou$ed %o %he .orld %ha% a Fradially $e. modula%io$

%eh$i a$d

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$o% >7 jour$al i$ .hih %o reeal %his .or# %o %he .orld >$ 19+? ;la# .e$% o

%o .i$ A>s Bamme Medal >$ 194? .hih? i$ ar%? .as due %o his .or# i$

PCM >$ 194? lier? Piere a$d Eha$$o$ u!lished %heir la$dmar# F-he

Philosohy o( PCMG i$ %he Proeedi$'s o( %he >7 -heir aer? a ri'orous

a$alysis o( PCM? o$*rmed %he meri%s o( 7eees ori'i$al o$e%io$

FPCM oJers a 'rea%er imroeme$% i$ si'$al8%o8$oise %ha$ o%her sys%ems ;y

usi$' !i$ary o$8oJ: PCM? a hi'h8$ %he year 2000 Fommu%ers

.ill re(use %o ae% %he delays a$d i$o$e$ie$es %ha% ee$ a modera%e

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jour$ey %o a$d (rom %heir lae o( .or# .ould e$%ail &e shall hae %o %ra$sor

%he !rai$s? %he s#ills o( %he s%aJ? $o% %heir !odies? %o %heir daily jo!s? a'ai$

i$oli$' $o% merely ordi$ary da%a Si$#s !u% a 'rea% ma$y ria%e %eleisio$

ha$$els as .ellG 7eees o$luded his rys%al !all 'a=i$' !y su''es%i$' %ha%

PCM .ould (orm %he ery !a#!o$e o( %he ommu$ia%io$s sys%ems ,e .as o

%he mar# .i%h %his redi%io$? !u% his su''es%io$ o( a reolu%io$ i$ ommu%i$'

a%%er$s may $eed a (e. more deades !e(ore i% omes %o ass

Al%hou'h PCM had ada$ed o$sidera!ly duri$' 7eeess li(e %ime? he $eer

lied %o see i% ou%'ro. adolese$e 7eees died i$ 191

/he &ord pulse7e(ers %o ulses (ou$d i$ %ra$smissio$ li$es? .hih are a $a%ural o$se

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aorda$e %o %he arrier si'$al %ha% is i$ %erms o( a$'ular or amli%ude Eo .e

are modula%i$' %he si'$alG

1dvantages of !odulation:

&i%h %he hel o( modula%io$? .e a$ i$rease %he $ %he a$'le modula%io$? a'ai$ %here are %.o diJere$% %yes o( modula%io$s

5re

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a$d radio ommu$ia%io$s

A$d .e are all .ell a.are %ha% radio ommu$ia%io$ use mai$ly (re

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5re$ (re$ %he amli%ude modula%io$? amli%ude o( arrier si'$al .ae is aried i$

aorda$e .i%h %he modula%i$' or messa'e si'$al !y #eei$' %he hase a$d

(re

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%ha$ %he modula%i$' si'$al

(re

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Disada$%a'es o( Amli%ude Modula%io$I

Addi$' o( $oise (or amli%ude modula%ed si'$al .ill !e more .he$

omared %o (re$ ulse .id%h modula%io$? %here are diJere$% %yes o( modula%io$ (or a$alo'

a$d di'i%al as sho.$ !elo.I

PCMI Pulse Code Modula%io$ (or A$alo' Modula%io$PPMI Pulse Posi%io$ Modula%io$ (or Di'i%al Modula%io$

PDMI Pulse Dura%io$ Modula%io$ (or Di'i%al Modula%io$

PAMI Pulse Amli%ude Modula%io$ (or Di'i%al Modula%io$

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34 ulse Code !odulation #C!$:

Pulse Code Modula%io$ is *rs%

i$%rodued !y Ale 7eees i$ %he yea

193 >$ %he ulse ode

modula%io$? A$alo' Ei'$al is

reo$s%ru%ed %o di'i%al si'$al (or

ease o( %ra$smissio$ !y usi$' %he

a$alo' si'$al samles >$ %eh$ial%erms? PCM .ill %ra$smi% %he a$alo' i$

di'i%al (rom? .hose si'$al is samled a

re'ular i$%erals o( %ime a$d

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is omle%ely re'e$era%ed !y eah reea%er? ma#i$' i% $oise8(ree a% %he s%ar% o

eah reea%ed %ra$smissio$

E%ora'e

A PCM .ae(orm may !e saed (or la%er rerea%io$ or lay!a# Ei$e PCM da%

is di'i%al i$ ori'i$? i% a$ !e s%ored usi$' a omu%er or similar deie A$

eHamle o( a o$sumer deie %ha% s%ores PCM da%a is %he Di'i%al ersa%ile Dis

DD: %eh$olo'y -he audio or%io$ o( a DD moie is e$oded usi$' PCM .i%a samli$' ra%e as hi'h as 192 %housa$d samles er seo$d -his PCM s%ream

a$ !e ied dire%ly %o a$ amli*er usi$' a di'i%al audio a!le? .here i% is %he

deoded i$%o a$ audi!le si'$al

$oded Ei'$al

A PCM si'$al a$ !e modula%ed i$ suh a .ay %ha% o$ly a sei* deoder a$

ma#e se$se o( %he u$derlyi$' da%a -his is use(ul .he$ %he da%a !ei$' se$%re

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modula%i$' si'$al or messa'e si'$al -his is a$ a$alo' %ye o( modula%io$ >$

%he ulse amli%ude modula%io$? %he messa'e si'$al is samled a% re'ular

eriodi or %ime i$%erals a$d %his eah samle is made roor%io$al %o %he

ma'$i%ude o( %he messa'e si'$al -hese samle ulses a$ !e %ra$smi%%ed

dire%ly usi$' .ired media or .e a$ use a arrier si'$al (or %ra$smi%%i$'

%hrou'h .ireless -here are %.o %yes o( samli$' %eh$i$ si$'le olari%y ulse amli%ude modula%io$? %here is *Hed leel o( DC !iasadded %o %he messa'e si'$al or modula%i$' si'$al? so %he ou%u% o( modula%i$'

si'$al is al.ays osi%ie >$ %he dou!le olari%y ulse amli%ude modula%io$? %h

ou%u% o( modula%i$' si'$al .ill hae !o%h osi%ie a$d $e'a%ie e$ds

Ada$%a'es o( Pulse Amli%ude Modula%io$ PAM:I

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>% is %he !ase (or all di'i%al modula%io$ %eh$i$ %he ulse osi%io$ modula%io$? %he osi%io$ o( eah ulse i$ a si'$al !y %a#i$

%he re(ere$e si'$al is aried aordi$' %o %he samle alue o( messa'e or

modula%i$' si'$al i$s%a$%a$eously >$ %he ulse osi%io$ modula%io$? .id%h a$d

amli%ude is #e% o$s%a$% >% is a %eh$i% re

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Pulse osi%io$ modula%io$ has lo. $oise i$%er(ere$e .he$ omared %o

PAM !eause amli%ude a$d .id%h o( %he ulses are made o$s%a$% duri$

modula%io$

Noise remoal a$d seara%io$ is ery easy i$ ulse osi%io$ modula%io$

Po.er usa'e is also ery lo. .he$ omared %o o%her modula%io$s due %o

o$s%a$% ulse amli%ude a$d .id%h

Disada$%a'es o( Pulse Posi%io$ Modula%io$ PPM:I

-he sy$hro$i=a%io$ !e%.ee$ %ra$smi%%er a$d reeier is re$ ulse .id%h modula%io$ or ulse dura%io$

modula%io$? %he .id%h o( %he ulse arrier is aried i$ aorda$e .i%h %hesamle alues o( messa'e si'$al or modula%i$' si'$al or modula%i$' ol%a'e

ulse .id%h modula%io$? %he amli%ude is made o$s%a$% a$d .id%h o( ulse a$

osi%io$ o( ulse is made roor%io$al %o %he amli%ude o( %he si'$al &e a$

ary %he ulse .id%h i$ %hree .ays

;y #eei$' %he leadi$' ed'e o$s%a$% a$d ary %he ulse .id%h .i%h rese% %o

leadi$' ed'e

;y #eei$' %he %aili$' o$s%a$%

;y #eei$' %he e$%er o( %he ulse o$s%a$%

&e a$ 'e$era%e ulse .id%h usi$' diJere$% irui%ry >$ ra%ial? .e use +++

-imer .hih is %he !es% .ay (or 'e$era%i$' %he ulse .id%h modula%io$ si'$als

;y o$*'uri$' %he +++ %imer as mo$os%a!le or as%a!le mul%ii!ra%or? .e a$

'e$era%e %he P&M si'$als &e a$ use P>C? 0+1? A7? A7M? e%

miroo$%rollers %o 'e$era%e %he P&M si'$als P&M si'$al 'e$era%io$ has $

$um!er o( .ays >$ demodula%io$? .e $eed P&M de%e%or a$d i%s rela%ed

irui%ry (or demodula%i$' %he P&M si'$al

Ada$%a'es o( Pulse &id%h Modula%io$ P&M:I

As li#e ulse osi%io$ modula%io$? $oise i$%er(ere$e is less due %o

amli%ude has !ee$ made o$s%a$%

Ei'$al a$ !e seara%ed ery easily a% demodula%io$ a$d $oise a$ also !

seara%ed easily

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Ey$hro$i=a%io$ !e%.ee$ %ra$smi%%er a$d reeier is $o% re

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Demodulation-o reoer %he ori'i$al si'$al (rom %he samled da%a? a Odemodula%orO a$

aly %he roedure o( modula%io$ i$ reerse A(%er eah samli$' eriod? %he

demodula%or reads %he $eH% alue a$d shi(%s %he ou%u% si'$al %o %he $e. alue

As a resul% o( %hese %ra$si%io$s? %he si'$al has a si'$i*a$% amou$% o( hi'h8

(re

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1nalog to Digital Conversion:

-he AVD o$ersio$ is

'e$era%ed !y arryi$' ou% %hree !asi oera%io$sI

5il%eri$'

Eamli$' Qua$%i=i$'

$odi$'

36Filtering :

-he *rs% s%e %o o$er% %he si'$al (rom

a$alo' %o di'i%al is %o *l%er ou% %he

hi'her (re

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-his !a$d8limi%i$' *l%er is used %o

ree$% aliasi$' a$%ialiasi$': -his

hae$s .he$ %he i$u% a$alo' oie si'$

is u$dersamled? de*$ed !y %he

Ny

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+y,uist7Shannon sampling theorem

5i'I 5ourier %ra$s(orm o( a

!a$dlimi%ed (u$%io$ amli%ude s (re$ %he *eld o( di'i%al si'$al roessi$'? %he samli$' %heorem is a (u$dame$%a

!rid'e !e%.ee$ o$%i$uous si'$alsa$alo' domai$: a$d disre%e si'$alsdi'i%

domai$: E%ri%ly sea#i$'? i% o$ly alies %o a lass o( ma%hema%ial (u$%io$s.hose 5ourier %ra$s(ormsare =ero ou%side o( a *$i%e re'io$ o( (re$%ui%iely .e eHe% %ha% .he$ o$e redues

o$%i$uous (u$%io$ %o a disre%e se% eHresses %he samle8ra%e i$ %erms o( %he (u$%io$s !a$d.id%h -he

%heorem also leads %o a (ormula (or %he ma%hema%ially ideal i$%erola%io$

al'ori%hm

-he %heorem does $o% relude %he ossi!ili%y o( er(e% reo$s%ru%io$ u$der

seial irums%a$es %ha% do $o% sa%is(y %he samle8ra%e ri%erio$ Eee

Eamli$' o( $o$8!ase!a$d si'$als!elo.? a$d omressed se$si$':

-he $ame Ny

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56 Sampling:

-he seo$d s%e %o o$er% a$ a$alo' oi

si'$al %o a di'i%al oie si'$al is %o samle

%he 5il%ered i$u% si'$al a% a o$s%a$%

samli$' (re% is

aomlished !y usi$' a roess alled uls

amli%ude modula%io$ PAM: -his s%e uses

%he ori'i$al a$alo' si'$al %o modula%e%he amli%ude o( a ulse %rai$ %ha% has a o$s%a$% amli%ude a$d (re

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96 uanti%ation and Coding:

Qua$%i=a%io$ I is %he roess o(

o$er%i$' eah a$alo' samle alue

i$%o a disre%e alue %ha% a$ !e assi'$e

a u$i( a$ i$u% samle is $o% assi'$ed a ( %he i$omi$' si'$al s%re$'%h i$ mirool%s is s?

a$d %he $oise leel? also i$ mirool%s? is $? %he$ %he si'$al8%o8$oise ra%io? E/N

i$ dei!els is 'ie$ !y %he (ormula E/N Y 20 lo'10s/$: EN7 is measured i$

dei!els d;: -he hi'her %he EN7? %he !e%%er %he oie

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-he .ea#$ess o( "ray odes is oor er(orma$e .he$ %he si'$ !i% ME;: is

reeied i$ error

A% %he des%i$a%io$ reeier e$d: o( %he ommu$ia%io$s irui%? a ulse ode

demodula%or o$er%s %he !i$ary $um!ers !a# i$%o ulses hai$' %he same

rder

&he$ more %ha$ o$e !y%e is used %o rerese$% a PCM samle? %he !y%e order

!i' e$dia$ s li%%le e$dia$: mus% !e #$o.$ Due %o %he .idesread use o(

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li%%le8e$dia$ >$%el CPKs? li%%le8e$dia$ PCM %e$ds %o !e %he mos% ommo$ !y%e

orie$%a%io$

Sign

>% is $o% e$ou'h %o #$o. %ha% a PCM samle is? (or eHamle? !i%s .ide

&he%her %he samle is si'$ed or u$si'$ed is $eeded %o u$ders%a$d %he ra$'e

%he samle is u$si'$ed? %he samle ra$'e is 02++ .i%h a e$%eroi$% o( 12

%he samle is si'$ed? %he samle ra$'e is 81212 .i%h a e$%eroi$% o( 0 >(

PCM %ye is si'$ed? %he si'$ e$odi$' is almos% al.ays 2s omleme$% >$ er

rare ases? si'$ed PCM audio is rerese$%ed as a series o( si'$/ma'$i%ude

oded $um!ers

Channels and (nterleaving

>( %he PCM %ye is mo$aural? eah samle .ill !elo$' %o %ha% o$e ha$$el >(

%here is more %ha$ o$e ha$$el? %he ha$$els .ill almos% al.ays !e i$%erleaed

Be(% samle? ri'h% samle? le(%? ri'h%? e%? i$ %he ase o( s%ereo i$%erleaed da%

>$ some rare ases? usually .he$ o%imi=ed (or seial lay!a# hard.are?

hu$#s o( audio des%i$ed (or diJere$% ha$$els .ill $o% !e i$%erleaed

Fre,uency and Sample

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A PCM s%ream has %.o !asi roer%ies

%ha% de%ermi$e %he s%reams *deli%y %o

%he ori'i$al a$alo' si'$alI %he samli$'

ra%e? .hih is %he $um!er o( %imes er

seo$d %ha% samles are %a#e$@ a$d %he !i%

de%h? .hih de%ermi$es %he $um!er o(

ossi!le di'i%al alues %ha% a$ !e used %o

rerese$% eah samle

E%a$dard samli$' resolu%io$s a$d ra%es

Commo$ samle resolu%io$s (or BPCM are ? 16? 20 or 24 !i%s er samle

BPCM e$odes a si$'le sou$d ha$$el Euor% (or mul%iha$$el audio dee$d

o$ *le (orma% a$d relies o$ i$%er.eai$' or sy$hro$i=a%io$ o( BPCM s%reams

&hile %.o ha$$els s%ereo: is %he mos% ommo$ (orma%? some a$ suor% u

%o audio ha$$els 1 surrou$d:

Commo$ samli$' (re

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Di?erential C!

alues are e$oded as diJere$es !e%.ee$ %he urre$% a$d %he reious alue

-his redues %he $um!er o( !i%s re$ a PCM s%ream?

%he amli%udeo( %he a$alo' si'$al is samled re'ularly a% u$i(orm i$%erals?

a$d eah samle is

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1pplications PCM is used .i%h-81a$d-83 arriersys%ems -hese arrier sys%ems

om!i$e %he PCM si'$als (rom ma$y li$es a$d %ra$smi% %hem oer a si$'l

a!le or o%her medium

PCM is also %he usual di'i%al me%hod used (or musi audio lay!a# o(

musi CDs &hile suor%ed !y DDs? DDs hae a 'rea%er olume so

%hey use Bi$ear PCM? .hih has a hi'her samli$' ra%e 8 u %o 248!i% a% asamli$' ra%e o( 96 #,=

Pulse ode modula%io$ is used i$ %eleommu$ia%io$ sys%ems? air %ra

o$%rol sys%ems e%

Pulse ode modula%io$ is used i$ omressi$' %he da%a %ha% is .hy i% is

used i$ s%ori$' da%a i$ o%ial dis#s li#e DD? CDs e% PCM is ee$ used i

%he da%a!ase ma$a'eme$% sys%ems

Pulse ode modula%io$ is used i$ mo!ile ho$es? $ormal %eleho$es e%

7emo%e o$%rolled ars? la$es? %rai$s use ulse ode modula%io$s

http://www.webopedia.com/TERM/T/T_1_carrier.htmlhttp://www.webopedia.com/TERM/T/T_3_carrier.htmlhttp://www.webopedia.com/TERM/T/T_1_carrier.htmlhttp://www.webopedia.com/TERM/T/T_3_carrier.html

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