~ " PRIVATE AND CONflOENTiAl

ENGINEERING DIVISION

VislttoResearchLabor.atories, Telefunken A. G., Hannover

/9fh. June, "1964

," ·Visit Report No.A-"084 1964/39 "

THE BR ITfS HBROADCASTING CQRP'ORATION

Vi ~11 t Eeport No. A--084

(1964/39)

111 • G. I) u:::le c:c, 15. U c ~, l~ . J.' 'le • E • }~ .. , i~ . {'l • .. E ~ I l. I~ 6 (Do::;].enCI Dopal'tr'ont)

i ... Il.I .. E .. E~.

(1".Cl. Parker)

oU~ .,,-/<

(i •. V. 1.01.'(1)

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Th1s Report is the property of the Brit1sh Broadcasting Corporation and may not be reproduced or disclosed to a third party in any form without the written permission ot the Corporation.

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t Heport No. A-084

9TH ,;mm 1964

Title

HITj(ODUG'f.LOU

SUDCJl.HHIEH m;iEHEiICE O~)CILLATOH CONTHOL

3.1 "Nov!--PALlf ••

3·2

4.1 Tho :i1odifie:c

4.2 l"urLhe:c deve10puentG

CONCn]~':>ION~)

6.1 DJ Glv-P AI. • 6. ~~ ;\1 ew-ll cvl-PAL •

6.3 Tra:rwcodinc; •• 6.4 He cOl:ll'lendationS

AC fl!mfL:sDGEJ'!IENT S

r~I~l"II~ILEN ClS~) • • •

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Engineering Division

Visit Report. No. A-084

( 1964/39)

PllIV ATE AND CONJ:"LDENT LIl..L

June 1964

VI:::rr 'TO IillSE~AHCH LABOH.ATOHIES 01" TELElUNKEl'~ A.G., lU\.NNOVEH,

9TH JlJI~E 1964

1. INT110DUCI1ION

The visit \'lUS made to the F{esearch Laborator:LoG of Te1efunIcon A.G., Hannovor in order to study the 1ate3t PAL-systeJil developments made by Herr Bruch and hL3 Go1lea;;ues. To date Herr Bruch has not published much inforDation concerning tranGcoding and mOL1t of the day cpent at the laboratory conci.sted of discuosing several of his nevl propooulf..' and seeincs demol1otrationo of one or G"I';o that have been inwtrumenteu. Herr Jo.EJcchke oft.he }'erncloldetechnisches Zentralamt, Darmstacl.t, was present durinG the discusGionG and demonatrationG.

2 • G EN EltP;L

'rhe fact that the PP..L signal is ;:101'0 re[,istant than the N'rSC s:Lgna1 Lo csrtain form::; of diotorl;:Lon leach, to the posoibili of tranG-coding bebrccm the livlTO GJrGliems, GO I.:-ha"t a PI\.L [)iC;;1al l:lay be UGod at. tho;)Q polnto in a transmisDion chain wherQ dh3tort;ion ,'Tould be trouble:30,:le in ter~'n8 of an N1'SC nignal.

lm ap:)rol.wll to l;he problem. of tra.1lfJcodlng 1'1'0::1 lJJI.L\jO NT:;C ha:" been publiDhed. 1 .1.11 lihlD a:cranGel'K~nt 1:,110 l'AL chrmrLnul1Go :;3:L:-;nulL; f11';3 t, sepurated into laud Q chro~]j.nance cO;ilponcmt.G b;;· lnea.nD of.' a ono-lino delay to;sether wIth DUi:, and cEfferonce circu:1. t.;:1, aD in the PAL dola;;r-l:L1o decode:·'. The outl)ut of the 11 iiU:'li:l:!.rli3 l1 circul t C01135.13 ts of Q chrO:Tl.nanco [3:L[~;1a.l[3, "LI/hllct the output of the di.:f.'ferenco circuit c;onsLs cr> of I chrOJ:l:.nanco iJignal~3 altornati.nsin phase lino by line; thene jhase a1tcr:lationD are then rer:lOvecl. by an (~lectronLG sVlitch. A:] a result, and Q chro:linc:u'1co

. slGnals, of sotlc'Ilha t reduG(;d~lorti cal reBolu t:'i.O:;1, are availabLe fOl' ru-co:nbinLn;:; vrith the Imni.nance Bi.cna1, frolJ whicll input chro.lpinance Gom:;?onentD have been rei:lo\Ted, Lo foru an riT:~c cOL1pon:Lto Gignal. ..Lt L3 apparent that this forn of transcoder~)Ort!LLtD no chango of subcarrier frequency and, aD far as ie knovm, derlonl::rtrationa of this arra.ngernont in the pa3t have al',m.ys taken placa using the PAL subcarrier to line-fre"iuanc:>' rolutionGhip, thus producing a non-standard NT:3C signul.

The nOil[ transcoding proposalf3 are more realistic in torms of the practical requiremento and Dome of ther:l rely on rocan t dovelop:ncn 1:;:3 in sub-

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carrier reference-oscillator c:ont.1'ol techniques. 1"01' the purpo~lO of c:lurity this repol't first revieHs theso devolop:nentt, and tihen otr~l:Lnon the tranncod:Lng prop03als.

;:>everal of the idea:3 and dOIT'310pment::;l de3cI'ibed by Horr Bruch, and outlined in this report, have not yet been covered by pa:tenGs and an tmclertaking \laS given tl:lI:d:;, in such eases, the infor:'1ation ";Quld be t:r-outed as eonfident:Lal. .. Herr Druch Is at the no:aent preparing a paper which vrill be published in the Tolofunkon Zeitung; hOvlevor, he haG undertaken to provide, in the nearrt,j.:no, an auvanco copy of hi f3 pupal' as 300n un i t~ hus been put into a suitable :Corn.

3. SUBCAH1UBH HEfEliEJ.!CE O:JClilil'roR CON'rnOL

3.1 llUm/_PAUI

Detai13 have beon publ.Lshecl :cecently2'df means controlli:1g the subcal'riel' ref'erencG-onclllatoI' in a decoder during the act,i YC portion of' each line; thiG control iG additional to that provided bytho nOI'Dul buret in the line-blanking interval. HeI'r Bruch refers to this technique arJ "IIow-P1U,11 • TvlO enbodir:10lyto of thie proponal i'lOTO doocribed. In the first, the oepaTa:te I and Cl, ch1~Oii1inance Gignals, obtained frOl;1 a one-line delay

• l-rith GW;l and difference circuits, are Dubj octad to i'ull-,'lave ro~(:'ii'icatio:1 and then nui tabl~r combined GO produce a '1'rave "rh030 frequency is tVI:i.CO that of subcarrler. It. can bo shovm that the phaGe of' thin double-frequency wave is constant and indepenuont of chron:Lnance phaGe angle. The second consists of multiplying the input PAL chrom,:tnance signal by the corresponding chro.ljJ:Lnance sLgnal that occurred uuring the previous line and ac;ain involvos a ono-li;10 delay. Th10 :pracess l'osulta, as before, in a I-lave ,'lhose frequency i~'l tw:Lee ·that of subcarrier and whaGe phaGe is independent of that of the chroJ::Linance f::lignal. In each embodil:lent the double-froquoney v,ave may them be UGod to control the phane of' an 1. c. Gubcarr:Ler reforenco-ondllator in the decoder throuehout the active line, provided that a sufficient amplitude of chronina.Dcc Signal is preGent. It ,·rill be appreciatod Ghat the subcarr:i.oI' control durinG the line is absent. in nonOChrOiJe areaa LU1d that bhe phase of the double-frequency vrave 18 in error at a hor:l.zo'1tal bounuary between areas of uH':ferent colour.

The New-PAL teclmique ,',ras illustrated by Herr Bruch In a GerioG of dmaonstratiorlG. first, it I'lUS [,hovm -~~hat a variation 1n the phuoe of the burst ~Jignal (i.e. a chrOL1inunce phaGo error independent of lu:dnance-si[)'11al l:lacnLt.ude) of ± 900 had neg~l.g:i.ble effect upon the pict.ure obtained frO!;l the HmI-PilL decoder. Tho sa::!10 degree of bursb phaGe shift "ran de:;lOnstrated uG:Ln:; N'rsc a.nd then uning PAL vrith a conventional delay-line PilL decoder (1. e. incorporating a crystal-controlled subcurrie:::, 1'ofercmce-oGc:Lllator); in t~lG cUSe of ruse the C0101..11' 01'1'01'3 were ve1'Y serious and, :i.nl;he Cai3G of 'I:;11e PAL \-l5.. th the conventional delay-l:Lne uecoder, the desaturation of'

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coloured areas I'ras vor] obvious. iJecondly, the 01':['0 e (:;;] o.f (LU:f01'cnt1.al-phase diDtortion lmre dcmonnGratC(l a Glide be flo'w'ers against a mainly Llonoehro;":lo bac1q:;round; it I'm,::; ~;tated thut ",Jlo degree of differontial pha::;::; distortion vraG of the ordol' of 25° fOl' a bright yellovr. '1l he offcet of such d:L::::tortion uD.Ln/..S Il'rUC; Uning PAL vlith a convontional delay-lino docoder reclUltod desaturation of the yOD.ovl areas. tJo effect;:; clue to distortion vlGro seen PAL vlit.h tho j'lo,'l-PAL decod~r'. effect::; of head·-to-tape "Ieloci ty variatlons :Ln a l'ecordm:' "I[C!'C siL'lUlaGed by int/roducing a chrominance phaDe error t.hat 'dUG zoro aL tho bec'"Lnnl"n cr 01·' e·ac'"·11 lJ·Yle·· 'o·ut p'~oc"~o

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onc head to another, bhe chrominance Bi.gnal could have a phaGe error of greater than 1[:500 , thus camrLng an incorrect lockinG of the f:3UbcarrLer reference-o:3cillator in the decoder. Hov,ever, thiG locking is corrected by the first burst, Gignal to be received after the head-fJ\'I:i.I~chi.ng operation • Herr Bruc:h pointed out; trIal:. the Nevr-PAL ~lUbcarrie"~ reforence-oscillator control tecJ:mique could pOG;3ibly be applied to the control of Colortec, tlmB vine; 801:1e add:i_ tional COTrec tion during the active port.ion of each line.

In reply to a que::rGI.on, he nta ted that no te,3tn had yet been carried out to det,GrI'rl.ne the serwitl.vity of the teclm:i.c~ue either to CvI interferonce or to ctrong lUJ'1.inanCe-fYLgnal GOl:tpOnentc; near subcarrier frequency.

3.2 lfN e,'l-N ew-PALlf

It vr:i.ll be appreciated that the New-PAL proposal is concerned only vrLth decoding technLIIue and i.s, therefore, not a proposal to t.1oclify the PAL syste.!.:1. Ho\..rever, Herr Bruch haD nO'i:{ f:lUggented that, by means of' a relatively sir:lplo rnodification to the PAL ChrOl":lLnance Signal, further ir:lprover:1ent.D can be r:1ade in decoding technique. He refers to the J:lodified

• Signal, toget.her ,,,1th the corresponding clecoding techniques, aD 1!Nevi-Ncw-PA:L". The modified fJignal contains a burst Hho~le phase, on snccesDive -lineD, alternates oY;:llJetrically about. the -Q chror:linance axis. Th1,::3 is illu8trated in . 1. In a preferred arranGm:1Crrt the burst ph line by li.no re:mltf.l in a DubcarricI' refer8nGe-O~lCillator output that also alternates .in phase lino b;y line. This wave ';lU.y then be used to dOl:l0dulute the L chrorlinanco SiGnal directly, thUG clLnpcnoing vr1th the need for an eloctronic sv/itch in the decoder.

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Herr Bruch sta\,odl:;hat, us far as f3en::rL ljivi. to diGto.cciorwLi.o concerned, the NevT-Nei'l-PAL decodinc;Lechnique is identical lIrith Nel,f-PAL. He pointed out that it would be possible to modify the r'AI, signal to the New-New-PAL form without rencieri:lg earli.er for:ns of PAL decoder uGeleGD, provided that the 1l1dent:;ification ll Signal, trfu'1Gmitted during the fielcl blanking and used to ensure correct operation of the decoder clcGGroniG s\·ritch, vrere ret,alned. 'rhe cr;yotal oDcillat.orD of Si];lple PAL and con-ventional delay-line PAL decoders vJ'Ould lock \dth a phane thal:. ie} t.he average of the tvlO burst phaseG racliated on GUCCe;3D:iv8 line:.3; thL;; average phaGe lie;3 along the -Q cl:1rOJ:l:i.nance axis. ThUG if the G:i.gnal vlere changed to conform with Ne~l-NGVl-PAL, the rel'orence-subcarrLer pha:oo in simple PAL and conventional delay-line !:'lUJ decoders would noeclto be phase shifted by 330 ; this is, in ~ffec:l:., a rotation of the hue c:ontJ'ol. 'rhe fact:. that the effective component of the burst used by the ~;.ix!ple PAL and conventional delay-line PAL decoders, under these condi t:1.on", t·JOuld be perhaps 3 dB lmmr in amplitude could be c(mpen:3ated by inc:cea:3iJ1G the arapli tucle of the alternating burst b;y 3 dB. A Nevf-PiJJ deeoder Ha;:; sholim to operate quite natLsfactorily mling the Nmr-Ne\'T-PiLL signal. HOI'JGvor, the line-by-l:Lne variation of say ± 450 Ln burGt phase m.ay be expocGod to absorb some of the tolerance of a Nevl-PAL cleGoder to pha;;;e errors.

4. THAN:3CODING

'1'he transcoding technique j:lont.ionetd in soetion 2 con;1if:lted, i::1 essence, of splitting the co:npo13L to DLgnal into chrO;:Li.nanco and lUGlinance 't'lignal8, transcoding the Ghroli:.Lnance si.;rnal to con1'o1'r:l to the required Dystecl and then fonning U::.e output adding a sO;~1m,rhat dOGraded l·l,ll:linance signal obtained from tho input. HerI' Bruch'D l1m,[ approach to transcoding relies upon splll:;Ung the input ::lignal spec Grur,l into tHO frequency bands. ldeally, the lovl-frequency band consi:Jt~l of lW.1inance components only and is passed direct to the output of the transcodor. TJ:lG high-frequency band conslsk; of the chrominanee signal plus all the high-frequency luminance cOr:Jponents. 'fhis high-frequency band is tran::5Cocled as an integral whole and is then added to the lQ\v-f1'e(lUency band to fan;] the output.

The success of this t,echnique depends to a eonsiderable ext.ent. upon the accuracy I'ri th which the input signal [;pectrU1.1 can be split into two bands Hithout introducing aI:lpli t.ude and group-delay errors at tlw "crossover!! frequency_ Up to the prOBent, Herl' Bruch ~~3 uaed a 10Vl-pa;::;:3 filter, with 801:1e group-delay correc (:':Lon, for ext.racting the lO1iI-frequency components and a band-pass cireui t for extracting the h:Lgh-fre:(uency components. He haB encountered B(X:1e problem~l with this arrangement and, at the J!1oraent, is Gonsidering the use of mini:num-phao8 net\'mrk~l only. In .. the opinion of the authors, this iB probably not. the baBe method of performing the splitting proceBs.

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4.1 The modifier

The transcodine of the high-frequency C:OJ:1ponenLs is effec:lied by a devi.ce Herr Bruch ha~l namedt.he "modifier lf • This 1:\odif1er consiGt[; of a balfu'lced modulator in "\vhich the input chrominance and high-frequency lULlinance cor:lponents are heterodyned by a 1'rave at tvrice the ~mbcarrier frequency. Of the tvlO sets of modulation products prod.uced, thone of 10vier frequency axe selected. The modifier can be shown to produce an out.put that is the complex conjugate of itG input; t.hus if the modif:Ler input has a chror:d.nance phase error, the modifier output has an equal but opposite phaDe error. The action of the modifier and it~) use in the tranDcoder are shown in Fig. 2. It vrill be seen that if the input to the transcoder consists of a PilL chrominance siGnal in vihich the fiTfJt line ha(3 a +1 co;nponent, the second line a -I component and the third line again a +I cOlaponent, the output of the modifier will consist, during the first line, of chronl:Lnance ,,,ith a -I CO];lponent, during the second line vrith a +1 COL'lpOnen t and during "the third line 'l'r.Lth a -I cOlnponent; the C2 com-ponent 1s uI1l:1odified. Thus, by rmi table operation, the electronic SI,rj:Gch can successively select, line by line, chrominarlCe and hieh-r£requency lUl21inance conponents from ei thert.he input to the modifier or from its output. In this way, an input PAL chrominance Signal :i.s converted into a form of NTSC chrominance signal in v{hich any phase error (associated with

• the PAL siGnal) is converted into an alternatine phai3e error in ·tho output 1'1'I";:}C ::ligna!. Corre:;pondingly, an ~~T8C chro12inance sienal can be converted into a. PAL chroninance Signal at the output. Hhen tranncoding froT1 PAL to N'rSC, the a.l ternating phase error in the output NTSC chrominance signal Inay be removed by passing the signal derived from the electronic S\'I1 t.chto a one-line delay and adding together the signals appearing at the input. and output of this delay. This process causes the phaGe error to be cancelled at. t.he COGt of a reduction in chrominance amplitude (and hence saturation) related to the cOGine of t.he phaae error. In addition, vertical chrominance resolution is somewhat reduced.

It vr:Ll1 be appreciated that the action of the ,nadiner is to produce a "mirror-image", about subcarrier frequency, of the high-frequency COl\lpOnents of the input Si£P'lal. If the input signal is of the tlequi-band" form, in vlhich the chrol;linance band\'lidths of the I and q (or H - Y and 13 - Y) signals are nominally equal and syrwaetrically disposed about subcarrler f. frequency, and if the splitting of the input-flignal spectrum is carried out efficiently, the frequency band occupied by the tranDeoder output is approJcLmate1y equal to the bandwidth of the input. This is illustrated in Fig. 3 vlhere (a) represents the input Dpeetrum, after sp1itt:Lne and (b) repre~3entD the output spectrun during a line in l"hich the output high-frequency band iB obtained fro.m the modif:Ler.

When, hOl'fever, the input 8ienal to the transcoder has the nor:::1.al f'orra of NTi3C or PAl~ spectruu (Le. narrow double-sideband Q chrominance fmd wide asy:nr;'JetI'ic-sideband I chroJ:1inance), and if the high-frequency band is

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to contain all the chrorrLna::tee .l.nfor'mation, to 1'0110\,1. F .. Lrst, the C1'0:::;[30V01'

t\'lO con:.lecluoncc8 \'1ou1:1 appoar of the t,VlO bund:] ;:llWt be

101t-rered and secondly, the bandlllid th is appreciabl;y groatoI' -than that of

occupied the input.

the output of the trmlGGoelcl' 'TlleD':? IJoin.trJ [11"'0 :i.llu;) Grated

in 4.

Herr Bruch di.el not comment on the prob1eciD posed if the crOSSO'Jor frcquency~rere to bo located GO that the Gingle·-side band CO::1ponen t of the .l chrOI1inance signal is included in[:'ho 10w-frequenG21 band; Guch an aITange-ment might possLb1y prove \'lorkable ,·,here tllJO LrarwcocLlng oporilt;imw are involved, the ;}ystem of the final outpu t being id on LiGal t.o thaL of the input. He tended to the v:i.ewthat 1 .. LI:,tle, if anythinG, would be 10Dt if NTSC and PilL signalc emplo;;rod only double-[)ideband chrol:1L~.1ance GignaL; 'dith bandHidths equal to that at. preDent allocated to Cl. chromLnancc. Ho did not describe, in any detail, the action of the mocLifier upoYlt.he frequency lUl,1i.nancc cor:ll:)Onent.s, l)u tit. will be apprec:J.a ted that thenG com-ponentf} are Lreated in an exactly sL;n:i.1ar Ic.anner to the cln'OE\inanco componen tG •

Herr Bruch then dOllonsl::.rateel transcoding frml equi-band NTSC (I-Tith the N'l';~:C Dubcar:der-'Go-line frequency relatiorwhip) to P1J.,. The output conSisted, therefo:ce, of a PAL 3i8"11a1 with the NTL;C Gubcarrier-to-line frequency relatiol1Ghip. Th.o output was Vim-lOe! in both colour and monochrome. ~l'he co10nr pictux'e lilaC marred vertical colULlns of sub-carrier elota on eolour tran3i tions and by a f3 tati .. cHlary and very vi:Jible crosi3-colour pat,tern in areaG of lUD.:i.nance detai1. Tho blaGk-and-vlhi Le picture showed a very visible ::mbGarrier pattern inclucUng vertical colmms of dots in area.s of saturated colour. Using a blac:k-and-I'lhite te(rt-card slide the renolution lITedges of the teal:,-card 1"Teremarrecl appreeiable beato betvTeen the &'Ubcarrier pattern and the lUJ:li.nance de [Jail. 'rhe transcoder utlcd vias ba:1ed upon the principles outlined above and incor-porated a erY8tal OSciLlator for generating the tllTico subcarrLcr-frequency wave. Herr Bruch then del;lonstrat:.eel tra.."'lsc:oding 1'1'0.::1 equi-band N'l\)C (ilTith the N'l'SC subearrier-to-line frequency relationship) to PAL (vrith the NTSC subcarrier-to-line frequency relationship) and back to NT~)C. Colour and monochrome pictures obtained at the final N'rSC output v/ere viewed and eould be compared v1ith corresponding pietures obtained from the NTSC input to the tranGcoding chain. In this caDe, the piG"!::,ures obtained by this double trarweoding 1t-lere ver:l sat:U}factory; the colour picture shovred the nor'J1al ::mbcarrier pattern on tranDi tl()fls betvreen coloured areas and the GI'o::m-colour "raG of the nor::.iul NT3C The black-and-\:lhito picture ahOl'18d the normal subGurr:i.er pattern in areas of colour and ~1hovTed a flatiGfaetor;;r reproducti.on of the re~,o:lut:i .. on vmc1gei3 of the monochrome Le[,t-earcl. HO\18ver, there ,-,rere DOJ::O urn,ranted effects Vii3ible tn tho high-frequency portion of the reno1ution ,'rodzo~3; ~lQj:10 do G pattern could be seen UJ'1d the pLeture Dhm1ed phane elTor~;) in that portion of the 1tJedge that correGponded 1:;0 the crODs-over frequ~ncy at which the t1ITO cor~ponGnt,s of the GPoctnu:l "\ITf.n'o 8oparated.

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4. 2F'urther development:::

Herr DruchLhen out.lined a p:copOiJccl extension of his tr

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Both 1'1'1':::>C and i)AL D:Li~]la1G \18:;:'0 r:lrLLutocl, tJ,o C'JCl l':lVO minute:3 or so. Littlo difJ'cI'oneo "\Jet;::) :Jeen lletMoen using the \j,VO that f:cor" a U.E.L". to V.H.Li'. ~1 on NT~)C or simple PAL reel a ::;l5.C;ht ad;ju:C:G::lCYlG of the bnc eont:co1.

HGlT Druch ha.c: l'ccent.l;y- a.cquLred a )10\>01:'0:1.a 19t1 C010111:' :coC.:ci·iIor incorporating a rec Gancu1ar tjube; hOvlever, this HUC; not ceem .La opcrat,ion. Finally HorI' Bruch lndLcated that, he is tho chal'uc t,c;r:LflGLc:3 of oor:lG 1411 and 17" recl~anGu1ar colour

6. conCLU:::;ImJi3

6.1 NE}"\,I-PA1

This :L8 a teclmique applied in u clelay-l:inc deeodc:;I'.Lt I'C;lOV;:;i3 saturation errors 1:1 the out~lUt whleh rermlt fro;;] f:i.zed-~Iba,i~e or rlLffc,rcntLal-I)11acG errorG ~ J\~') (le~::lo~]G tro.. (~~J(l it V1D .. fJ "\;r8~~:~:/ o1"foG \7"0 ~l'nd :Ln t~,~lO 0 n:i.'~}a of the authorfl uhould be [,[,wlicd in vim! of .U;c UPi?li.caLion tob'UDiJCod .. Inventigation of il~D noise perl'or:jlanCC wmlc.1, oX[u(lple, ofLYlLC:J~·e;~::,. Although the NevJ--PAL referonco-ose:Lllator control ·c,oclm:Lcluo th.o crystal 08eillutor an 1.c. o:.Jci.llator of re1utivel;;r i.3Lllplo docJ:i.£~n, it J.:3 unlikely that. it could re:3ult in an:/ uP1H'eciublo Duving in tho con i~ of a domeotic roeoivor doeoder.

6.2 NG\I-No1;l-PAL

Alt,hough, f3t.ric blJ :3peak i.ng, th:l.c Pl'opo:lul :l u of n:n: L,o''? (us a re;mlt of the ehan~~e in t.he ion of t.he rurjiUGCc1 [lignul) j.t iG aimed at a furbher i;]provonont i.n decoder Oi)Oration. The need for identification ;3ignulD ic rOi:l •. 1Vod and thi~l ca:1 tho decoder Em-m "vel' , t,ho Nml-,\JevJ-PAL :3ic;nal cun contain thoi ... dont.:U'ieuL:Lon Dl.Gna.li, ~,o aD to be uimble r.>ir:plo-PAL, convon t. ; .. ona1 dela,;l-li..ne PAL and No\!·-j)AL decodern. In the authoru' opLnion Lhe lJCI,],-NmJ-PAL LU; not of pri~e int~rest at. pres~lt.

6.3 'rranseodin[;

IIc:cr ;3ruch hUB [nude a ~;ore reali.;:;tic upproad: to this p:coblo'l. IUs dOI:1oiwtrationiJ Gho\! t11al~ tTcG fro!:, rIT~,)C to PAL :;:'ol.Lo'l.Jod trarl:JGocllnG PiLL -GO .NT:3C V·Of3 U D~,~ti:3~C

,

- 10 -

6.4 Hecomi:ienclat:Lo:l.G

HerI' Bruch has undertaken to l::ake eve:c;y effort to loan equipmmt to the BIlC in order that further Gtud:ie:3 may be carried olr:~. 1"11'8-(:., 1.1 Yle'il-PAL decoder unit should be available very Goon and :Lt if, recor:u:cnclod that 1[;[3 chaI'acl:,c1'int.ic~l be r:,eunured in detail. Secondly, two non-::Lnally identi.cal trarlGcoclerG Dhould ruDO be available Goon. 'Eheir j.ntrinGic character:L8ti~s Ghonld bo ;:1eaGured and, a:eranGing them. :in a suitable sequence, the tolerances of the link conncctingthel:l Dhould t,hen be deterr:llned.

7. ACKH01'iLEDG ji.:JIE:NT ~3

The authorG ,'/ish to eX}JreGs their appreciation for the efforts made by Herr fjruch and hiG colleag1..1.eD in describing and demonstrat:i.ng tho clevelopuentG rev:i.evred in this report.

1. BHUCH, H.: lI'rx'an8cod.er N'ESC 'PhaGe Alternai::;i.on Line' Ct).!U~)~ NT~3C NOlTla:L'i, E.B.U. Ad-hoc Group on Colour Televicion, COf.l.T.(E)29, Section 5.

2. 13HUCH, H.: liThe PAL Colour Television System, Basic Principlen of nod.ulation and Demodulationll; TranD].ution prepared for the participants of the r,lQoting of the Colour Tolovision Sub-Group of the .C.C.LIl. Study Group Xl, February 1964, of a paper to be published in IfNachrichtentechnische Zeitschr:U't1l.

3. "Nevl Approaches to Subcarrier Regeneration from the Colour Signal, for the PAL system w-:i.th Delay-Line Receiver", E.B.U. Ad-hoc Group on Colour Television, Com.T. (E) -;6.

Printed by BBC Research Department, Kingswood Warren, Tadworth, Surrey

+1

-Q----------------~--~-------------------+Q ...

/

/

/ /

/

" / burst

.......... ........

-1

.... .... .... h . ........ c rommance ....

............ .... ~

.. . ), Fig.1 Vector diagram of chrominance and burst In New- New PAL

Signals transmitted during one line

Signals transmitted during succeeding line

.. ,

, +1 +1

-a------------~-----------+a -a------------~-----------+a

-1 -1

(a) Chrominanca vactor diagram of input (b) Chrominanca vactor diagram at output showing a chrominanca phasa arror cp of mOdifiar, for input shown in (a)

..... ..... ,. , input

(sub-c:arr ier fr~qu(lncy fs)

..... -7

~---------------~ I I I I I

balanc~d I I modulator

I~

2fs

I I I I

I I I

-I I I I I I I I I L _____________ --'

•

~Iectronic:

L SWitch... , outp

....... -;,

modifi~r

(c) A transcodar consisting of a modifiar and an alectronic switch

Fig.2 Transcoding' by means of a modifier

ut

low -froquency luminanco

components

~ 1'0~---------------------+~-----------------, ::J ~

t

high - frequoncy luminancca

componcants t

" chrominanco components

o 1·0 2'0 3'0 f(Mc/s)

(a) Input signal sp(lctrum aft(lr splitting into

low and high - fr(lqu(lncy bands.

low- frequency luminancca components

~ . ~1'0~------------------~-------------------~

high - frequency luminance components

t .. =a. E Cl

ell .~ .. Cl -; L.

o 1·0 2'0 3'0 feMc/s)

(b) Sp(lctrum of output signal in which th(l high - fr(lqu(lncy

band has b(l(ln obtain(ld from th(l modi.fi(lr.

Fig 3. Transcoding an "aqui - band)' colour signal

chrominance components

,

low - frl2qul2ncy luminancl2

componl2nts

high - fraqul2ncy luminanca

componl2nts ~ t

~ ~1'0~------------~--------~

:0= a. E a ~ .~ +' .Q ~ L..

o 1'0 2'0 . 3'0 ( (Mc/s)

(aJ Input signal spactrum of tar splitting into low and high -fraquancy bands.

chrominanca componants

low - ,raquancy luminanca componants

high - fraquancy luminancl2

.g 1· Ol----------"-------------'l .::J ~ a. E a ~ > :g III L..

(Mc/a)

(bJ Spactrum of output signal in which tha high - fraquancy band has ooan obtainad from tha modifiar.

Fig 4. Transcoding a "wida - band It. signal