BSTJ 30: 4. October 1951: The Davisson Cathode Ray Television Tube Using Deflection Modulation. (Jensen, A.G.)

6.5 MB·English

‘The Davisson Cathode Ray Television Tube Using
Deflection Modulation

Dy ALG. JENSEN

lakers Ha bi wn crnazed by Be CN Bae

HE present day cosa cable roa! Band ranuminson aysten wa

develop ering the ely 188 x ws eigally ooncsva as
‘metas for multi-channel telephone trssmission, During the sme periad
the rapidly developing television ast wae prndcing video sigale roping,
wwiler and wider frequenry ands We ear very sonn vealed, therefore,
{at This cousa system wold ler el acral tn ve Cans
ef such wide band television signals. Tae ely deve'apment culpa
fn the installation of «conan cable route fin New York to Palade.
‘Tain aye wan desig to pve 40 Ween chance oF 9 ingle
200 ke Wlevision chante nd hath types of tans. wer succstlly
seemed drng ae of donation 472

The waning cipmest used ‘oe puoducing the television signals fo:
these denna wna dovelapod under the divtton of Dr HE. oes
sa the Ball Telphone Taboratories, It we designe! to san sista
‘85mm mation pietare lm an conte of asx foe ste disk rotating at
10 apm and having 20 lees nase roo te petiphery. Te ts
truce elvis al of 240 Tne ao 2 Fares, ooo
ga badd of about 80 kloeyeles,

"Fr Wis save pei cane the well Enowa work of Dr. Davison inthe
Gehl of electnasdifecction® Tis work had seule alzo ia important
sdvances in electron optics ad inthe develepzent ofthe aarp Fosse,
ell defined electron bet. Te was natural, thezfors, that Dr. [ves chou
cuss with Dr, Daviston the possbity of designing a cathode ray tube
‘ule of slate igpaying pete frm theLelevion squat
Sel above. The trom of the conte ns tek Dr Davison, th
the cove and able collaboration af C.J. Cubic aaderunk to design aad
farsract the abe deere! inthe follwing yes Ts this conection it
tho alo be mentioned that he Set experimental ame af the tae
‘were built by GH, Reiter mile the [ater engineering for Emsited produc
iow as cari ont by H.W. Weinhar
“The disk scanner was & near ransmiier co the plimle of Ce
goal toa cre tly qe] tothe flan Teghenes. "Ta fume]
oqutement for ening ‘abe tae therfore as tated by Dx. Davison
Ian ex'y memoreadum

TS erm il ae proportional to Beam current or mms sees
Se tw Inn cunt i t2e rev tae shot be ropes] to ge
rel voltage; te dations of Iran eusrent by sgval wllage should Be
liner, Flare tu nee his reqrement eis in elsicaiov nf ne values

Sn repeavetton, aed hen degsetures ener are marked ft Jad
to nstilactony plesurcs

1 was this fondmemal rome. af a eam corene deel proportion
to fut wise, wich ed Inthe develcpaent af 9 take employing dedee-
toe modoletion, ive i type of tedulstion in which the maing
Waltage causes the el tron kez to be defeted sero» defining serio
jn sech a manrer That inrvarng mounting voltage wil cause a leper
fice te bers tops hnoagh te apr ad theres he eight
tess of te seeen pronoatianedy tothe meron voltae The pace
OF tis ty nf moat ie satated in Fi

Figure (a) shows a erie ir if eletrns pasig trough the sit S
(perventcue to the plaae of the peer) and aeranged to form & shexp
ine nf the sli the plane of the sseare aperture 5 The relation of the
tie mage to the square apron ison i Fi. (8), A bie voltage i
pled esis the modular ples Wy wd AP 0 chat the ait imege fls
ssf the syuatespartare for no sgn voage. As signal velege > mp
pied aero the madtlstor plate the si age will ive seoss the npet=
Ture sich a mange tht the reser ael atc of the beam beyond he
sri propeaioaa to sgl velage (for email! engies of detection,
ss ede),
ravistor cxrmanr way TeuRVIEN FoR sr

Leyond she aperace the electron Yeas enters projet las 5y-
tem eesignat to prject neve ston nage of tthe res
sent screen ofthe ‘tbe, Tn order to toil further moan of te bey

| ; L aes

in the pgm fens sytem tf eget that the Beas be mnataine

mall id. ie tube ins fad ot be deleted ye mation as a Fig
1M}, Ta secomplich she second pat af muting plate 8 and AFL

avis CATMODY RAY TEERUIION TORE 350

in add an cn connected wo At und 3,3 indicted ia Tig. 12. Now
sen sgoalwolage i paid, the rleetnon nem ieinlane, vather Ua

Alefected, acroae the spertine ae the porn uf Une hese etorag the

Projection lene syste is maintain ia proper clguaont with tho tube
"The cma set ronuptcal system of the tbe is indicated echemt
tally n Fig 2,8 dimensional coe section of the tube ie shown in Fig. 3,

hile Figs, nd S show rechaniesl deal Ube asl. igure 6
the tne tate, held By Me. Calc,

Refering to Fig 2, he pes, PS, 2,20 and PY are metallially
‘connected tgetier with separating metallic eyes to form the stat
tural “lane” ofthe etic letra serombly, They are eonnested to the
internal Aqatdeg coating tnd hed at grow pleat

‘The backing pte 7, ment F, ad elmaar aperture platen P, and Pe
constitste the electron course and condensing lens eprom aoe Faneton

“Pes muy eh singe nt

wision exon way seems FORE sot

|S to peoduue ae intense “oc sp of electrons ia the ple of the ait
aperre 5 (Fig. 1,

‘The Hlameat Fis made of tungsten fll nthe shape of «cross (Fig. 3)
tnd fed by divectcuevour with opposite ead of Ch cross connected to-
feces, This costcucioningures 2 nearly fon lemperature over Ue
‘nce aren uf the eros analy ninimdaen reagete ele ae up by the
Fumes carant, which woald other tend to dru the eecton opt
fal ssinetey- ie Hemestcestance te apnicnaely 1 lem al he eae
eat IO expete. The hip caisson cueeat devaly om 2 tungsten Ea
rent mas exported to eet in 8 more nee Toel spot then ould be
Dnucrahie wth anomie ested etre. Alun ohe arge metalic stactne
invite the tebe sight tend to comee devetivition or peeoning ofan ie
rath

1 ie mecianiea alignment were perfect the “Yoca spo of electrons
‘woul ll directly on the ait aperture. Hecause of unavoidable small mise
Migueacate eal particularly due lo the fact that Une Samant ras ib wot
Peet fat such perfect symmetry cannot Le insured without some cor

ctions These eotections exe supplied by ¢ socalled collimating unit
Ch. 0. Phe anit conse of em slecrragnot with ingle pele
per (hig. yan by appy'ng mal coring voltages ad curren
he the “foal pt ete ei is rt rena: fal Ue
tater pation of the at epertce S.A sacra identical colinsting unit
(CPs Cos is mounted ater the vi, i oder to ceutr che ait image on the
quae apeetare 8.

‘The thee csc aperture place PS, Pend Py constitute the socalled
tuoduletr lens system and serve to fora ga electron image ofthe ait 5
fon th square epercureS with a mogninestion ef I. Accurate focussing
iemptsnst hy ost the peal the pte Pa

‘The action of the daar plates MyM aad MaRS ha ley beow
osered. The photograph in Fig 4 stows the modulator pete assembly

‘The sot of thee cieulae apertare plates F2", Py and PY comprise the
jens len yet, hich form a lei ing of the equate apee-
ure s* upon tie duoteeson seeen with a mayaikension of S'1, Proper
focussing accompli ed by adjstig the paent of pace

"ro cea of el azsun‘es in the Inceal comers af tae tube ovsing,
sven fo teste the eth’ el ach predates il dete
or rangle sf 4° from the erties andy hy prover aesting the ol
“aor pb to pmdae practialyaniform magelic El, ih
‘eosin Inlet hen he sen

Tecan wf he rorsplcael mechanical say Snide ele there
vas orginally come difcaty in propery degusing the tubes and ene
Taina vaemen. Phe euler roel wer Une emtinucsly pun,

Dnswisow @ARMOn? kay sLEvRION TORR mss

‘nd a oto Slamert manomator waa usd for checking preture. The
tebes used during deniastatios were sealed ul, bot the mromeer was
retained as own a he photograph in Fig. 6 Tr ace the hot tata,
fnment acted a8 a getter which aucosllly Kept the presare down to
boat 10° min He

The apetuie 5 was 6? square, With 2:1 mnglcation tis rested
inn seunnog ine height on the seen eoecsponding to 4210 line pice
of shost 7 8 ines

A stationary spot viewed on the sercen stow shaxply deta settan
ular erenaoetion of approximate srfom, Drightaes, Adjusted for no

ig. 7-Seenat dee af node curve

overlap thi resulted nat eld th only fine cation of ln ste
tore. I the ime of the st falling on the aquare sperture Sis prtectly
focussed, with eeges peal! to the ides a the aperane if ro stray ee
trons ate present duo to secanlteyerviion or ober ease, and te
‘leeteons i the bet al: have the sume thar} emission energy, then the
‘arve of beam cutent yeraus tclatorvultoge wld be ne sow’ a
Tie 7. The curse veo unt the lading ee of he ai enters the sper
fore The corm then incest i trees a ints when
the lt ile the spectre, Ifthe alt wider thin he apertare the carve
vel have a Bat lp and il Chen decrease Tneriy ag the tralng edge of
the alt waves cro the apace

‘The setae! mulation erve dd not show shacp corners, bat was
rounded both abi an bottom a cated the dnt ines ia Bg 7.
‘The dispersion of thermal velocity of the electrons cnoes “chromate”
aleration of the condensing lens wstem (Py; P) wich therfore fms 8
66 emt. svstn HFEMMEAE JOURNAL, CeTUME 1981

“Socal epot of non-eiform denny This in ton rests in ror wid vores
sf Cre tmaluation cane Eves, the near portion ofthe ipdulton eve
‘urrpnlel tory eure ratio a abou 101.

Sa wil be seen Srom the curve, the tbo maybe ee cpaly we for
cither postive or negative moduli, bt inthe éeonalins pve
duo wae employed

‘An actual modulation curve for the teller wl for 4 ive pictues
fs shown in Fig. 8, The dotted line fnicaes the maton heaters
Tithout aay iiodifcation, mle tae sok carve show Ure improveeneat

“TTL! vA

att |

ear eutof eblened by inconporsting w non-fnane rel ia he oatpat
age othe video ampitr. Wily his exit, Finest moulin as ob
Tail over a bgxtnese range nearly 10021

‘Due tothe veresle with of ee acunnng spol i obvlous eat con
ventions! apertae equalisation & not appli. The wile of she rectan
ler spt cages from rasan &¢ fa brighlnees to sexo or rr n>
Er the decp shade ln oer wore, the ert apature equalization
trould bea aneton of Inghtiese, Some chemical eonpatatonsideated
{hac the efectivehorinstal teoivtion, without eay aperiore msalzadon,
tnigit be nell ahove the verte! rsaiow detennined by 220 ins. That
this woe ecualy ses iaiened Hythe fet shat, by arbi ie