Pioneer tuning fork User manual

AudioandVideoServiceGuide No.8
TUNING
FORK
PIONEER*
ORDERNO.GGF-606

CONTENTS
PartsInformation
SwitchesandRelays1
BasicTheoryofVideoSystems
NTSCandPALTVSystems12
MeasuringInstrument
PatternGenerator16
OnePointServiceTechnique
TroubleshootingPowerAmplifiersafterRemovingPowerTransistors...21
NewTechnique
LaserVisionwithDigitalSoundDisc(LDD)23
NewProducts
NTSC1/2"and8mmHomeVideoCassetteRecorders(VCR)27

PartsInformation
SwitchesandRelays
Variousswitchesandrelaysarebeingemployedinelec-
tronicequipment.Theyhaveonlyonefunctionofopen-
ingandclosingelectriccircuits.Theirspecificationsdepend
onperipheralcircuits.
Herewewilldiscussthefeaturesofmetalswitchesandre-
laysemployedinPioneerproducts.
Photo1 SwitchesandRelays
1

Switches
Aswitchcompletesorbreaksthepathofa currentorsends
itovera differentpath.Itsoperationisdigitalbecauseits
outputis"1"or"0",or"high"or"low".Therearetwo
typesinswitches,conventionalmetal-contactswitchand
contact-pointlessswitchorelectronicswitchmadeofa
transistororanIC.Theelectronicswitchisomittedhere.
b)SlideType
Aconductivepieceslidesandengageswiththeotherpiece.
Thishasa self-cleaningability.Itscrubsoffbyitselfthe
resistivefilmofdustandsulfiteformedonitscontactsur-
face. Thisissuitablefordealingwithsmallcurrentand
notforswitchinginhighfrequency.Fig.2 showstheprin-
cipleofslidecontacts.
1. Contacts
Contactsaretheheartofa switchwhereanelectriccircuit
isopenedorclosed.
MovablecontactFixedcontact
Open Closed
1.1Material
Contactsaremadeofsilver(Ag)anditsalloy,copper(Cu)
anditsalloy,gold(Au)anditsalloyorotherhighlycon-
ductivematerialstomaketheresistanceata contactpoint
lowerthan100m 12. Thematerialshavebothmeritsandde-
merits.Theyshouldbeusedintherightplace.
1.2STRUCTURE
Therearetwotypesofswitches;pushtypeandslidetype.
a)PushType
Inthistypecontactismadebypressinga conductivepiece
againsttheother.Thisissuitableforfrequenton-offoper-
ationofa largecurrentata highspeed.Fig.1 showsthe
principleofpushcontacts.
Fig. 1 PrincipleofPushContacts
2
Fig. 2 PrincipleofSlideContacts
1.3Symbols
Thereareseveralkindsofswitchsymbolsasshownin
Table1.Thesymbolseffectivelyshowthemechanismof
switchesandfeaturesofcircuits.
Contacts Symbols
Pushtype
Slidetype
Table1 VariousSwitchSymbols
Fixedcontact
Movablecontact

2. TYPESOFSWITCHES
2.1 Classificationby USES
Theycanbeclassifiedintothree;power,selectoranddig-
italswitches.
a)PowerSwitch
PowerswitchconnectsordisconnectsanACpowerline
totheprimarywindingofa powertransformer.Thisswitch
hasbeensodesignedtostandhighheattodealwitha large
currentwhichgeneratesarcsandheatwhenswitched.
Thecontactpiecesshould,therefore,bemadeofa mate-
rialwhichhasa highmeltingpointandshouldmovequick-
lytominimizesparks,andthegapbetweenthecontact
pointsshouldbewideenoughtopreventthepiecesfrom
meltingandsticking.Ifthegapisnarrowortheopera-
tionisslow,thearcwillcontinuefora longperiod.Fig.
3showsa typicalpowerswitch.Thecontactpointsare
madeofsilvercadmiumoxide(AgCdO)andareoperated
quicklywiththehelpofa spring.AllPioneerproductsem-
ploypowerswitcheswhichhavepreliminarybeenapproved
bytheauthoritiesofsafetystandardsineachcountry.
MajorsafetystandardsareUL(USA),CSA(Canada),
SEMKO(Sweden),DEMKO(Demmark),NEMKO(Nor-
way), BS(GB),VDE(WestGermany),EI(Finland)and
SEV(Switzerland).
Bs(Ag-plated)
BsorCu
AgCdO
BsorCu
-Bs(Ag-plated)
Terminals
Fig. 3 ContactPointofPowerSwitch
b)SelectorSwitch
Selectorswitchisa multipositionswitchthatpermitsone
ormoreconductorstobeconnectedtooneofothercon-
ductors.Thisisusedinthefollowingcircuitstothesecon-
darywindingofa powertransformer.Mostswitchesare
forselectinga signalandsomeforswitchinga DCcur-
rent.Herewewilldiscusstheswitchesforselectingsignal
channels.AstotheswitchesforopeningandclosingDC
circuitsandforsensingvariousconditions,refertotheitem
"2.2SwitchesClassifiedbyFunctions".
Switchesforselectingsignalsusuallyemploythesliding
mechanismwhichscrubsandcleanthecontactsurfaceby
itselfbecausethesignalstobeselectedareverylowinvolt-
age, smallincurrentandarehighlyaffectedbytheresis-
tivedustfilm.Figure4 showsthemechanismofa linear
slidingsignalselector.
Theclipormovingpieceismadeofsilver-platedphos-
phorousbronzeandthefixedpieceissilver-platedbrass.
Lowtenacitygreaseisappliedonthecontactsurfacesto
protectsilverfrombeingaffectedbythesulphurintheair.
Thesulphuraffectssilver,formsa resistivefilmonthesil-
versurfaceandcausespoorcontact.
Terminals
Fig. 4 LINEAR SliderTypeSignalSelector
Thereareshorting(make-before-break)andnonshorting
(break-before-make)typesinthisswitch.Fig.5showsthe
difference.Type(a)onceconnectsandtype(b)onceopens
allterminalsofA,B andC whenswitching.Generally,
shortingtypeisusedinmuters,attenuators,mode-
selectors,etc.andnonshortingtypeisusedinfunction
selectors,tapemonitors,etc.
Fig. 5 ShortingandNonshortingTypesofContacts
c)DigitalSwitch
Theswitchexclusivelyusedina digitalcircuitiscalled
digitalswitch.Thisisalsoa kindofsignalselectors.
Generallytheyareusedinkeyinputanddatacircuits.
3
Clip
Conductivepiece

2.2SwitchesClassifiedbyFunctions
a)RotarySwitch
Rotaryswitchiscapableofselecting,making,orbreak-
inganelectriccircuitactuatedbya rotationaltorqueap-
pliedtoitsshaft.Mostswitchesofthistypeareforselecting
signalsandsomeforswitchingpower.Herewewilldis-
cusssignalselectors.Thisswitchiscapableofswitching
multiplecircuitswhenswitchwafersareassembledinmul-
tiplegangs.Generallyeachwafercanselect11terminals
whichareapartfromeachotherby30°.Thisswitchusually
hastostepoverseveralunnecessaryterminalsbeforereach-
inga desiredpoint.Thecontactpointsareofslidingtype
andhaveanabilityofselfcleaning.Withthesefeatures,
thisswitchisusedforselectingfunctions,modes,speak-
ers, etc.Photo2 showstypicalrotaryswitches.
Photo2 TYPICAL RotarySwitches
4

b)Push-buttonSwitch
AswitchINwhicha buttonmustbedepressedeach TIME
thecontactsaretobeopenedorclosed.Microswitchand
tactswitch,however,areexcludedfromthiscategory.
Push-buttonswitchescanbeclassifiedbyuses,numberof
keys, andmechanismsasshowninTable2.
Nonlock(momentaryorpress-to-talk)typeopensorcloses
A circuitonlyINtheperioda keyisdepressed.Releasing
thekeydeactivatestheswitch.
Powerswitchesemploypressmechanismandsignalselec-
torsemployslidingmechanism.A signalselectorhasgener-
allytwocontactpointsfortwotoeightcircuits.
Table2 Push-buttonSwitches.
Lock/release(interlock)typelocksthenewlydepressedkey
releasingotherkeys.
Self-locking(latching)typelocksbythefirstpressand
releasesbythesecondirrelevanttothestateoftheother
keys.
Lock/releasetypecancontainmanyswitches,dealswith
manycircuitsanddoesnotrequiretopassunwantedcon-
tactpointstoreachthedesiredpointunliketherotary
switch.Withthesefeaturesmulti-gangpushswitchoflock/
releasetypeissuitableforselectingfunctions.Switchesof
singleandmulti-gangself-locktypesareusedinmuters,
filters, tapemonitors,etc.andthoseofnonlocktypeare
usedintapedeckRECmuters,keyinputsofdigitalcir-
cuit,etc.Insteadofpushswitchesmanytactswitchesdis-
cussedlaterarebeingusedindigitalkeyinputcircuit.
Multi-gangpushswitchhasallfunctionsoflock/release,
self-lockandnonlocktypes.Photo3 showstypicalpush
switches.
Photo3 PushSwitches
5
Pushswitch
Powerswitch
Signalselector MultipleKey
SingleKey
Lock/release
Self-lock
Nonlock
Self-lock
Nonlock

C)SlideSwitch
Theoperationofthisswitchismadebyslidingitsknob
backandforth.Thisissuitableforswitchingsignalsbe-
causemostofthistypeslidea contactpieceona fixedpiece
andscrubandcleanthecontactsurfaces.
Thistypeisdividedintotwo.Oneisoperateddirectlyand
theotherindirectlywiththehelpofanadditionalmecha-
nism.Theformerisnotmountedonfrontpanelbutisused
forselectingsubsidiaryfunctionsbecauseitsoperational
feelingispoor.
Thelatterisfurtherdividedintotwo.Onesimplyslides
acontactpiecebackandforth,andtheotherhasa spring
insideandreturnsthepiecetotheoriginalpositionwhen
thefingerisreleased.
Mostswitchesofthistypehavetwoorthreecontactsand
twototwelvecircuits.Thedirecttypeisusedforselecting
FMde-emphasis,AMchannelspaceof9kHzor10kHz,
carstereo'sspeakers2 or4,etc.Theindirecttypeisfor
selectingREC/PBofa tapedeck,portablestereo,etc.
Photo4 SlideSwitches
d)Leverswitch
Leverswitchisbasicallythesameasthesingle-keypush
switchandhasa leverforrapidlyopeningandclosinga
circuit.Snapswitchdiscussedlater,however,hasbeendis-
tinguishedfromit.
Itiseasytooperatetheleverandtofeelselectorposition
witha fingeralthoughitoccupiesa largespace.Thisis,
therefore,employedonlywhenthepanelspaceislarge
enough.Theuseisthesameasthatofsinglekeypush
switchsuchaspowerswitch.
Photo5 LeverSwitches
6

e)SnapSwitch(ToggleSwitch)
Thishasa depressingmechanismforoperatingata high
speedandismainlyusedforswitchingDCpowersources
andforsensingsignals.Toggleswitchisa two-position
snapswitchoperatedbya leverandispopularlyusedas
apowerswitchinmeasuringequipmentbutnotincon-
sumerproductsbecauseofitsunfavourabledesignand/
operationalfeeling.Herewewilldiscussthepopular
mechanically-assistedtypeemployedinDCpowersupply
circuitsandsignalsensercircuits.Thishasoneortwocon-
tactsandonetofourcircuits.Thisisusedasa carstereo's
powerormotorswitchora positionsensorofa
mechanism.
Fig. 6 SnapSwitchesanditsOperatingPrinciple
Photo6 SnapSwitches
Terminals
Fig. 7 StructureofPlateSpringSwitch
7
.(a)Open— (b)iskeptawayfrom
(a)whenitisfree. (b)Themomentofclosing— (A) and(B)comeonthesame
verticalline.
(c)Closed— Themoment(A)
movesfurtherrightward,the
springpushes(b)against(a).
Spring
f)PlateSpringSwitch(LeafSwitch)
Whentheoperatingstrokeislonganditsdispersionis
large,thecontactplatesmadeofspringabsorbtheexces-
sivestrokeandmaintainstableON/OFFoperation.The
mechanismisthepress-to-contacttype.Thisissuitablefor
sensingmechanicaloperationandswitchingDCpower
sources.Fig.7 showsthestructureofplatespringswitch.
Theleftoneisopen-airtypeandtherightoneiscasedtype.
-Platesprings
Lever Case

Mostoftheswitcheshaveoneortwocontactpointsand
circuitsbecauseoftheirstructure.Anadditionalmecha-/ nismisrequiredtooperateitata highspeedbecauseit
hasnosuchmechanismasthatofsnapswitch.
Photo7 PlateSpringSwitches
g)Microswitch
Thisiscasedina smallbox,isoperatedata highspeed
bya pressuretoa springandallowsa largecurrent.This
requiresanadditionalmechanismtobeoperatedbecause
ofitsdifficultyinmanualoperation.Thisisusedfor
switchingpowerandselectingsignalchannels.Fig.8 shows
thestructureofa typicalmicroswitch.
Thishasoneortwocontactsandmostlyoneortwocir-
cuits. Liketheplatespringswitchthenumberofcircuits
islimited.Themicroswitchwhichhasanactuatorhasboth
featuresofplate-springswitchandsnapswitch.
Springs Terminals
Actuator
Fig. 8 Microswitch
Photo8 Microswitches
8
Pin
Case

h)TactSwitch
Thisis A kindofdigitalswitchesandispopularlyusedin
keyinputcircuitsfordigitalICsincludingmicrocomputer
ICs. Voltagedropbythecontactresistanceinthisswitch
isnegligiblebecausetheappliedvoltageislow(5V— 15V)
andthecurrentissmallindigitalcircuits.Therefore,com-
parativelyhigh-resistanceconductiverubberispopularly
usedinplaceofa metalpiece.Theresistanceofmetalcon-
tactsislessthanoneohmandthatofconductiverubber
ismostlyseveralhundredsohms.Thishasonecontactand
onecircuit.Someswitchesamongthoseemployingcon-
ductiverubberdirectlyopensandclosesa partofgilded
copperpatternofa printedcircuitboard.
Insulatingrubber
Conductiverubber
Photo9 TactSwitches
i)OtherSwitches
Thevariationsoftheaboveswitchesare:
•Flexibleswitch(remotecontrolswitch):A variationof
rotaryandpushswitcheswhichemploysa flexiblewire
fortransmittingpush-pullforceortorque.
•ReedSwitch:Thishastwooverlappingmagneticreeds.
Itkeepsanairgapbetweenfreereedends.Thereeds
attracteachotherwhenmagneticinductionisapplied.
Thisistheswitchportionoftherelaydiscussedlater.
•See-sawSwitch(rockerswitch):Popularyusedasa pow-
erswitchyearsago.Thisisomittedherebecausethis
isnotpopularnow.
Photo10OtherSwitchesa,b,c
9
Metal
spring
contact
Terminals Terminals
Fig. 9 StructureofTactSwitch

2.3 PartsNumberingSystem
OUR numberingsystemofswitchesisasfollows:
Table3 NumberingSystemofPioneerSwitches
Relay
Relayisa kindofswitchactivatedbyelectro-magnetic
force.
1.BASICSTRUCTURE
Arelayismadeofanelectromagnetandcontactpieces.
Whilethecoilisopen,themovablepieceC touchesthe
fixedcontactpieceB (breakcontact).InFig.10,whena
currentisappliedtothecoil,C isattractedbythesole-
noidandtouchesthefixedpieceA (makecontact.)
Spring
Fig. 10StructureofRelay
2. KINDSOFRELAYS
Relaysareclassifiedintofour;powerrelay,protectivere-
lay,smallcurrentrelayandreedrelay.
2.1POWERRELAY
Powerrelaythatfunctionsata predeterminedvalueof
powerisusedinsurgekillercircuitsofhighpowerampli-
fierstoreduceinrushcurrentwhichflowswhenpoweris
turnedonorinACpowercircuitsremote-controlledby
aninfraredray.Towithstanda highvoltageandlargecur-
rent,thisrelayusesSilverCadmiumOxide(AgCdO)at
contactpoints.Thedimensionsofcontactpiecesarelarg-
erthanthoseoftheothertoradiateheat.
10
Coil Yoke
A B
PartNumber Descriptions
SA-000
SB-000
SC-000
SD-000
SE-000
SF-000
SG-000
SH-000
SK-000
SL-000
SM-000
SN-000
SX-000
SAOOOO)
SBOOOO)
SCOOOO)
SDOOOO)
SEOOOO)
SFOOOO)
SGOOOO)
SHOOOO)
SKOOOO)
SLOOOO)
SMOOOO)
SNOOOO)
SXOOOO)
Power switch
Rotary switch(tobeterminated
with a binder)
Rotary switch(tobeterminated
with a bindersmalltype)
Rotary switch(others)
Rotary switch(slidetype)
Microswitch
Push switchortactswitch
Slide switch
Lever switch
Snap switch
Sea-saw switch
Plate springswitch
Others

Photo11PowerRelays
2.3SmallSignalRelay
Smallsignalrelayisemployedinpreamplifiersformut-
ing,selectingequalizer'stimeconstant,etc.Structureis
thesameasthatofprotectiverelay.Thiscanbemadesmall
becauseitdealswitha smallcurrentoflowvoltage.
Photo13SmallSignalRelay
2.2ProtectiveRelay
Protectiverelayisforpreventingdamagetoaparatus.This
dealswiththesignalofa widedynamicrange,fromresidu-
alnoiselevel(lmV/O.lmA)tothemaximumoutputlevel
(28V/3.5A(100Woutput))at80load.Withthisswitch,
whenthecontactsurfacesareoxidizedorsulfurized,small
signalcurrentwillbeblockedandsoundwillbemutedby
thenonconductiveoxideorsulfidefilmformedonthesur-
facebecauseitcannotscrubthefilmoff,oritcannot
cleanby itself. Thefilmcanbebrokenifthepowerout-
putishighwhenthepowerisswitchedonandoff.Such
acase,however,isunexpectedbecauseamplifier'svolume
controlisusuallyturneddownwhenpowerisswitchedon.
Protectiverelay'scontactpointsaremadeofgildedsilver
topreventtheoxidizationandsulfurizationordoublepoint-
ed,ortwocircuitsareusedforonepurposetomakethe
contactperfect.Inprinciple,thefailurerateofthedual-
contact-pointrelaybecomes1/X2ifthatofthesinglecon-
tactpointrelayis1/x.
2.4ReedRelay
Reedrelayismadeoftwoflatmagneticstripsof52-gold
sealedina tubefilledwithinertgas.Itscontactpointshave
beengilded.Whena currentisappliedtothecoil,theleads
attracteachotherandclosethecircuit.Whenthecurrent
stops, thecircuitopens.Thelargestfeatureofthisrelay
isthatcontactpointsofthisrelayarenotaffectedbythe
environmentalconditionsbecausetheyareprotectedbyan
inertgas.Theuseofthisrelayisthesameasthatofthe
smallsignalrelay.
Glasstube
Terminal
Fig. 11ReedRelay
Photo14ReedRelay
Photo12ProtectiveRelay
11
Au-plated Terminal
52-gold(Ni52%,
Fe48%)
Coil
Inertgas

ThemainworldcolorTVsystemsareonlyNTSC(National
TelevisionSystemCommittee),PAL(PhaseAlternation
Line-by-Line)andSECAM(SequentialColoursa
Memoire)althoughtherearemanystandardsin
monochromesystem.Allofthethreesystemstransmit
colorinformationinadditiontoluminanceandsoundin-
formationtomakebroadcastsignalcompatibletoboth
monochromeandcolorTVreceivers.
CompositecolorTVsignalincludesluminanceandchro-
minancesignals,vertical-andhorizontal-syncpulses,
vertical-andhorizontal-blankingpulses,color-burstsig-
nalandsoundsignal.Table1 showsthespecificationsof
thesystemsandcountriesconcerned.
HerewewilldiscusstheNTSCandPALsystems.Themain
differencesbetweenNTSCandPALareinthemodulat-
ingmethodofchrominancesignalalthoughbothofthem
employQuadratureAmplitudeModulation(QAM)sys-
tem.
ColorSystem NTSC PAL SECAM
CCIR
Standards M M N B,G H I D B D,K K' L E
Scanning
Lines/frame 525 625 819
FieldFrequency
(Hz) Mono60
Chro59.94 59.94 50
LineFrequency
(Hz) Mono 15750
Chro
15734.264
15734.264 15625 20475
VisionWidth
(MHz) 4.2 5 5.5 6 5 6 10
ChannelWidth
(MHz) 6
B:7,G:8
8 7 8 14
Vision-sound
Separation(MHz) 4.5 5.5 6.0 6.5 5.5 6.5 11.15
ColorSubcarrier
(Hz) 3579545 3575611.49 4433618.75 foR:4406250foB:4250000
ResidualSideband
(MHz) 0.75 1.25 0.75 1.25 2
VisionModulation
Polarity -+
SoundModulation FM AM
SoundFrequency
Deviation(KHz) ±25 ± 50
SoundPreemphasis
(lis) 75 50
2-channel Sound
Japan,
USA W. Germany
Countries Barbados Brazil Argentina,
Paraguay,
Uruguay,
Belgium HK,
Ireland,
UK,
S.Africa
China(PR),
Korea(PR)
E.Germany,
Egypt,
Greece
[BH],
Iran,
Iraq,
Lebanon,
Libya,
Maulitius,
Morocco,
Saudi
Arabia,
Syria,
Tunisia
Bulgaria,
Congo,
Czecho-
slovakia,
Djibouti,
E.Germany,
Hungary,
Poland,
Reunion,
Togo,
USSR
Guyana,
Ivory
Coast,
Martinique,
New
Caledonia
Monaco
Countries
IN],
Bermuda,Canada,
Argentina,
Paraguay,
Uruguay,
HK,
Ireland,
UK,
S.Africa
China(PR),
Korea(PR)
E.Germany,
Egypt,
Greece
[BH],
Iran,
Iraq,
Lebanon,
Libya,
Maulitius,
Morocco,
Saudi
Arabia,
Syria,
Tunisia
Bulgaria,
Congo,
Czecho-
slovakia,
Djibouti,
E.Germany,
Hungary,
Poland,
Reunion,
Togo,
USSR
Guyana,
Ivory
Coast,
Martinique,
New
Caledonia
France,
Luxem-
bourg
Countries
Chile, China(Rep),
Colombia,Costa
Rica, Cuba,El
Salvador[K],
Ecuador,Guatemala,
Haiti, Honduras,
Japan, Korea(Rep),
Mexico,Panama,
Peru, Philippines,
Samoa,St.Kitts,
Surinam, Trinidad
Tobago,USA,
Venezuela
Algeria,Australia,Austria,
Bahrain, Denmark,Finland,HK,
Holland, Iceland,Indonesia,Italy,
Jordan, Kenya,Kuwait,Liberia,
Malaysia,Malta,NZ,Nigeria,
Norway,Oman,Pakistan,Portu-
gal, Qatar, SaudiArabia,Spain,
Seychelles,SierraLeone,Singa-
pore, SriLanka,Sweden,
Switzerland,Tanzania,Thailand,
Turkey,Uganda,UAE,
W.Germany,Yugoslavia,Zambia
HK,
Ireland,
UK,
S.Africa
China(PR),
Korea(PR)
E.Germany,
Egypt,
Greece
[BH],
Iran,
Iraq,
Lebanon,
Libya,
Maulitius,
Morocco,
Saudi
Arabia,
Syria,
Tunisia
Bulgaria,
Congo,
Czecho-
slovakia,
Djibouti,
E.Germany,
Hungary,
Poland,
Reunion,
Togo,
USSR
Guyana,
Ivory
Coast,
Martinique,
New
Caledonia
France,
Luxem-
bourg
Table1 WorldTVSystems
12
NTSCandPALTVSystems
Basic Theory of Video Systems

NTSC SYSTEM
Oureyesaresensitivetoorangeandcyanonsmallspots
andnotsosensitivetomagentaandgreen.Whena colored
thingbecomessmall,itscolorapproachesorangeorcyan.
Thecolorbecomesinsensiblewhena coloredspotbecomes
smaller.So,a widerfrequencyrange(1.5MHz)hasbeen
allocatedtotheorange-cyaninformationthantoGreen-
Magentainformation(0.5MHZ)inNTSCcolorTVformat.
Allcolorscanbemadebymixingred(R),blue(B)and
green(G)light.Theycanalsobemadeof(R-Y)and
(B-Y)signals.*
*R, G, B and Y stand for red, green, blue and luminance
signals. Y-signal is made up of 0.3R + 0.59G + 0.1 IB and
produces monochrome pictures.
ColorsignaliscarriedbyI andQ signals,whichareon
theaxesadvancedby33°from(R-Y)and(B-Y)axes
respectivelyinthephasordiagramshowninFig1.They
areoutofphaseeachotherby90°.EIandEQsignalsare
madebythefollowingequations:
Ei = 0.74(Er-Ey) - 0.27 (EB-EY)
EQ = 0.48(Er-Ey) + 0.41 (EB~EY)
TVreceiverreproduces(ER- EY)and(EB- EY) signalsin-
steadofreproducingEIandEQwitha simplifiedcolorcir-
cuitwhichhasonly 0.5MHZ bandwidthbecauseitis
practicallyunnecessarytoreproduceEiandEQthrough-
outthefrequencyrangeof 1.5MHZ beingbroadcast.
Tomakethebroadcastsignalcompatibletomonochrome
andcolorTVreceivers,chrominancesignalisbeing
insertedintothevacantspacesofluminancesignalinthe
frequencyspectrumasshowninFig.2.
Whena coloredprogramisreproducedona monochrome
receiver,whitedotsmayappearduetothebeatingbetween
picturecarrierandcolorcarrierasshowninFig.3.These
dotshavebeenminimizedbydeterminingthechrominance
subcarrierfrequencyata halfofthehorizontalscanning
frequencymultipliedbyanoddnumber.
fs = fff/2 X 455 = 3.579545 (MHz)
fH:Horizontal scanning frequency, 15.734 Hz
+Uaxis (PAL)0°
Fig. 1 l/Q(NTSC)andV/U(PAL)Quadrature
Componentsofa Vector
Fig. 2 SpectralDistributionoftheTVSignal
Brightness reversesinthenext frame.
Fig. 3 ColorCarrierInterferenceReducedbyInterleaving
13
-Uaxis 180°
Luminancesignal Chrominancesignal
Odd multiple of
fh/2 (117)
Oddmultiple offh/2 (455)
Integralmultiple of//?(286)
4.5 MHz
Luminancesignal Chrominancesignal
Videocarrier fp
Chrominancesignal
subcarrier/s Soundcarrier
fa
fp
fs
QI
Bright
Dark
1/3.58jus
1stscanningline
2ndscanningline
3rdscanningline
4thscanningline
Brightparts Darkparts
Brightnessreverses onthe nextline.

Thenthebrightnessof3.58MHzdotsisinvertedlineby
lineandframebyframeandismadeinsensible.Toavoid
beatinginterferencebetweenthecolourandsoundcarriers,
thehorizontalscanningfrequencyhasbeendeterminedat
15,734(15,750-16)Hz.
Thetransmittingmethodofcompositechrominancesignal
byplacingitsbandsofenergybetweenthoseofluminance/
PALSYSTEM
NTSCandPALemployQ.A.M.systemofchrominance
signal.Theytransmittwochrominanceinformation
simultaneously,employa synchronizeddetector,andhue
andchrominancesaturationaredeterminedbyphase
differenceandrelativelevelbetweentheburstsignaland
chrominancesignal.
Thereare,however,somedifferencesbetweenthem.PAL
usessimpleweighted(R'-Y')and(B'- Y')color-
differencesignalsofequalbandwidthtomodulatethetwo/
signaliscalled"interleaving".Theluminanceandcarrier
colorsignals(EY,ECn)arerepresentedbythefollowing
equations:
EY= 0J0ER+ 0.59EG + 0.11EB
ECN = a(ER— Ey) cosoost -hb(EB— EY)sin o)St
a: 0.877, b: 0.493, fs:3.58MHz
quadraturephase(butequalfrequency)subcarrierswhile
NTSCsystememployscomplexI andQ signalswhichhave
unequalbandwidths.
Themostsignificantdifferenceisinmodulatingmethod.
PAL'smodulationaxisof(ER- Ey)invertsevery1Hwhile
thatofNTSCdoesnot.Thecarriercolorsignalisrepresent-
edbythefollowing:
ECP = ± Q(ER — EYJcosodSt + b(Es — EY)sinwst
Fig. 3 BandwidthofEuropean625-lineSystemfor
BandsIV/V(ChannelWidth:8MHz).
PALreceiveraddsandsubtractsthedirectandlH-delayed
signals.Adderandsubtractorputout(B- Y)and(R- Y)
signalsrespectively.Thedemodulatedsignalbecomesan
averagebetweenthetwoadjacentlines.Thustheresolution
becomesa littlelowerthanthatofNTSCinprinciple,and
themodulatingcircuitbecomescomplicated.PALsystem,
however,hasa higherallowanceinphasedistortioninthe
transmissionsystem.
ThePALsystemnullifieshueerrororthephaseerrorof
colorsignal.Ifthetransmittedsignalismagentaforsever-
alscanninglinesandissubjectedtoa phaselagof0°,the
vectorsofa pairofreceivedlineswillbeasElandE2in
Fig.5.Theevenoroddlinesinvertedbya transmitterare
reinvertedbythereceiverandthelowerlineofthepairleads
fromtheoriginalphaseasE2\WhenElandE2'are
integratedandaveragedvisuallyorelectrically,thephase
errorisnullified.Iftheerrorislarge,theintegrationbe-
comesdifficultandcolormovesupanddown(Hanoverbar
orVenetianblind).
Reivertedlowerlineofa pair
(reddishmagenta)
+V
Receivedlowerline
Fig. 5 PhaseErrorCorrectionwiththePALsystem
14
K,G
l,L
G I
L,K
MHz
/c-4.43
0.75
1.25
urn
•1.1
1.6-
Burst
Colorsubcarrier
Burst
nlineER-EY(n+1)line(n+2)line
Fig. 4 PAL'sTransmissionVectors
E'2
Ei
Transmittedoriginalhuemagenta
Receivedupperlineofa pair
(bluishmagenta)
+U
E2

Tofindoutthepolarityofthemodulationaxisof
(ER-EY), burstsignalphaseisshiftedby90°everyline.
Ifthechrominancesubcarrierfrequency(Fc)ismadea half
ofthehorizontalscanningfrequencymultipliedbyanodd
numberasinNTSCsystem,the(R- Y)componentwill
beinphasebetweentheadjacentscanninglines,andver-
ticalstripeswillappear.Thechrominancecarrierfrequen-
cy,therefore,isdeterminedbythefollowingequation:/
fc = (284-1/4) X fH+ (fH/625) = 4.4336 MHz
Provided: fH= 15,625 Hz
Thusthecolorcarrierenergyisinterleavedinluminance
signalspectrumfo/4 outofphasefromit.Tomakethe
dotsinvisiblein625-linesystem,25Hz(fu/625)isadded.
Fig.6 showsthewaveformsofNTSCandPALvideosig-
nalsduringthefieldblankingperiod.
1stfield
Pedestallevel
_Equalizing _
pulses
Verticalretraceblankingperiod
Endofthelast(bottom)
horizontalscanning
lineinthe2ndfield
Beginningofthe1st(top),
lineofthe1stfield
Videocarriernulllevel
Endofthe1stfield Beginningofthe
2ndfield
Videocarriernulllevel
Pictureinformation
A.NTSCSIGNALINTHE1stAND2NDFIELDS
Fieldsync
datumline
a-
Burstblanking: 1stField
Burstblanking: 2ndField
Burstblanking: 3rdField
Burstblanking: 4THField
Burstphase
135°('NTSC-lines') Burstphase
225°('PAL-lines')
Fig. 6 Videosignalwaveformsduringthefieldblankingperiod
SECAMSYSTEM
IntheSECAMsystemthesub-carrierisfrequency
modulatedby(R- Y)ononelineand(B- Y)onthenext
insteadofbeingmodulatedbythetwocolordifference
signalssimultaneously.Detailsareomittedherebecause
wearenotmanufacturingvideoequipmentofthistypeat
themoment.
15
Blacklevel
Whitelevel
2ndfield
Equalizing
pulses Verticalsync pulses Horizontalsync
pulses
4thField
1stField
2ndField
3rdField
b.625-linePALvideosignal

PatternGenerator
ATVpatterngeneratorisrequiredfortestingandadjust-
ingVCRs(videocassetterecorders),TVreceiversandTV
monitors.Herewewilldiscussthefeaturesandfunctions
ofLeader'sNTSCtypegeneratorLCG-396referringto/
theknobsandcontrolsofitsfrontandrearpanels.
ThefunctionsofPALtypegeneratorssuchasLeader's
LCG-399aresimilartothoseofNTSCtypealthoughPAL
systemisdifferentfromtheNTSCsysteminstandard.
LCG-396(NTSC)LCG-399A(PAL)
Fig1 FrontPanelofPatternGenerators
©. Power Switch
©. Power Indicator
®. —®. Pattern Selectors
(3). Cross Hatch
Thispatternismadeof21verticaland16horizontalwhite
lineswitha dotinthecenter.(Crosshatchanddotsare
displayedonthesamescreenwithLCG-399.)Thisisfor
adjustingstaticanddynamicconvergenceofa colorpic-
ture, verticalandhorizontalamplitude,verticaland
horizontallinearityandotherrasteralignments.
®. Center Cross
Forcenteringpictureonthescreenwiththeknobsofver-
ticalandhorizontalpositioncontrol.
(5). Dot
20(vertical)x 15(horinzontal)whitedotsforstaticcon-
vergencealignmentandfocusing.(Crosshatchanddots
havebeenintegratedintoonepatterninLCG-399.)
(6). Raster
Red,blue,greenorwhiterasterisselectablebydepress-
ingthisbuttonandturningRasterSelector# 17.These
rastersareusedtoadjustcolorpurity.Whiterasterlevel
isof100%luminanceandisforadjustingwhitebalance
ofcolorpicture.Blackrasterisobtainablebydepressing
COLOR,CHROMAandLUMINNANCEbuttons.
16
Measuring Instrument

®. Color Bars
Colorbarpatterniscomposedofcolorbarsinorderof
luminance.
Upperpattern:Fromleft— White,yellow,cyan,
green,magenta,red,blue
andblack
Lowerpattern:Fromleft— Q,-I,*whiteandblack
Thissignalisforchrominance(chroma)circuitadjustment.
•Refertop-13.
White
(75%) Yellow Cyan Green Magenta Red Blue Black
White(100%) Black
Example
VCRAdjustingluminanceandchromalevels
AdjustingAutoColourControl(ACC)
Balancingchromalevel
Settingburstgate— phaseandam-
plitude
Measuringmoire
TVreceiverAdjustingchromacircuit
AdjustingACCcircuit
Thewhitelevelofuppercolorbarsis75%inamplitude.
When100%whiteisrequired,usethewhitesignalofthe
lowerpattern.
®. IQW Off
Upperbarscanbedisplayedonfullscreenwiththisswitch
depressed.When100%whiteisrequired,turntheIQWon.
*IQsignal:InNTSCsystem,thecolorinformationis
broadcastonI andQ signals.Thesesignalsareonthe
orange-cyanandgreen-magentaaxesrespectivelyforef-
fectivebroadcasting.Theaxeshavea 90°phasedifference
eachother.PALsystemusesU andV axes.Ref.PI3.
Fig2 ColorBarPattern
Fig. 3 ColorBarSignalwith7.5%Setup
®. Chroma Off
Thecolorbarscanbemadecolorlessbydepressingthis
switch.Thisgraypatternisusedtoadjustthelinearityof
pictureamplifiercircuit,whitebalance,etc. Upper-
pattern
-Lowerpattern
Blacklevel
Pedestallevel
Fig. 4 LuminanceSignalofColorBarPattern
17
Q -S
Color
burst
White
Yellow
Cyan Green
Magenta
Red Blue
Black
Q -I
Weighted: Theamplitudeisreducedtomeetthesensitivityof
oureyesandtoavoidoversaturation.
HSync

@. Luminance Off
Luminancesignalcan be removedfromthecolorbarsig-
nal by depressingthisswitch.Thischromasignal is used
tocheckthephaseandamplitudevariation of chromasig-
nal inthe pictureamplifiercircuit.
(Q). Chroma
Chrominancelevel of colorbars and rasters is variable
within the range of ±20%.
R-Y(Modulated by ER-EY)
C:Chrominancesignal
'[Composedsignal of (R-Y) + (B-Y)]
B-Y(Modulatedby EB-EY)
/Time
Twocolorsubcarriershavebeenmodulated by (R-Y) and(B-Y)
signalsrespectivelyandthenaddedbeforebroadcasting.
Fig. 6 EnlargedWaveform of ChrominanceSignal
(3.58MHz)
Fig. 5 ChrominanceSignal of Color Bar Pattern
EB-EY=-0.3ER
Fig. 7 VectorDiagram of CarrierColorSignal(Red)
A:Amplitude
Y:Luminancelevel
(b)Non WEIGHTED (C)WEIGHTED
Fig. 8 PhasorDiagrams of ColorBars(NTSCandPAL)
18
Amplitude
1/3.58 jus
90°
ER-EY=0.7ER
Red Magenta
180°
Burst
Yellow
Green Cyan
Blue
0°
90°(ER-EY)
270°
/A:0.762 \
VY:0.3 /
113.2°
/A:0.834\
V Y:0.41 /
45°
/A:0.90\
VY:0.89/
173°
/A:0.834\
VY:0.59 '
225°
/A:0.762\
\Y:0.7 /
293.2°
/A:0.90\
V Y:0.11 /
353°
/A:0.63 \
V Y:0.3 /
103.5°
Red 90°(ER-EY)
Magenta
/A:0.59 \
VY:0.41 /
61° Qaxis
(EB—EY) 0°
/A:0.45 \
V Y:0.89 /
167°
Yellow
180°
Burst
( A:0.59 )
\Yi0.59 /
241°
Green
Cyan
270° /A:0.63
\
\Y:0.7 /
283.5°
—Iaxis
Blue
/A:0.45 \
I Y:0.11 /
347°