BSTJ 30: 3. July 1951: Interaxial Spacing and Dielectric Constant of Pairs in Multipaired Cables. (Maupin, J.T.)

7.2 MB·English

Interaxial Spacing and Dielectric Constant of Pairs in
‘Mullipaived Cables

By 7. MAUPIN
faa tin! 261881)

ria ict tas Cie ne a daca med ene
ttn wt of dee cad ca etn

Iemnasnerion

A cae oases of tn indivi lated conductor, of emi
salle cia enaeerion, hi Rave bea isto together a long,
felt ond traded into ele cre wll sui pas. Xt as not ben 9
ible tone goto abe le esl characteris of suche cru 0
{erms ois ales nples payee coviguraon. Fo: ths reason, meskode
large yof sx pio ar have vs the pao corelae ysl
{nt etal chareteainuf-calfpated cable

“The capacitance o ary sata ol conve Frere & Nomoger ous
rmcéiun ie tlyinocioa! to the ele i solar of the edi
{The dices nlx cat yest no harpenmae, Yeas bs deseo in
Ging oft horcgenceae distoevie which woul rade tao cere ane
tance, In uliter br the dcketrc properties of he inelacing mee Ce
Captetant of als pir is ertermined hy the lepton af the exited
Caner wi sxpoct € one other ad eh eapees to che urea ire
poe ae

Ty pastel, the irteasil spans teen tae ies a pa hs a
ssc afoot on rapactane, The atersss sept iesitarmned 3 he
Silty of the Pmaabon hr tet eformycian shi tn eomnssive feces
entered it ealing sents, Ua. se capaitarce oa exble pal
Tanglydepenint onthe sashes! st ester properties a tbe
‘let ingueton, «nx sveton of the ratve eis oan neuen
'S the apasitree level, fv a farticular cenductor zug, resulting fom a
geen cable spe allwatice or sper

‘Vapevem lh juies obo oper pinnae! eles ae show
ta crv wile deviations im eapedlance eam oeeur ever. tho te
sphce yes pe allowsne ievaecaaaly coustant. The aforementone
‘ersstnveiors 1 wus EAH 655

plies! methods of capactancespace analysis do nat provide any insight
sto wlctes then devillon are due uv imma Ee ms anil pray
fessor the delete pesperto f ae isultin, a bot

‘With spect :o sme clea and physical characte evident
that there ea clase aalogy betwee the cable a ad “ea” balanced
biolded pir consisting of two aesight and parallel slid cylindrical co
‘hustors ences ine eindcl conducting shield with the centerline
the par coinciding with tae axis of the she, A crosesecon ot such a
‘Gee eehown in Fa. . The erste are naa fom one ene nd
for the steld by abomageacous dicectic

‘Rigorous mathematical espeision for the capacitance end inductance
of to deal pir in terms ofits dimensions and dlc comstent hve bees

rived by the Mathomtion) Recarch Group of the Laboratories and
tales, Measuted vals ofthe capacitance and inductance fa iven cable
ti when substituted ints these expen, deerme eta dinensione
hla dislectsc constant vale which dese an ies pair ang the uate
Captcitance ct inducranee ae the cable pa, The extet to wbich these
iEsntaed vale: sepreen tas cabesonitioas depersi on tae accuracy
ihe nent equclerse ofthe Gen sise

‘The jerome thin papi to deeb few simple bat dict eaped
sna, results of which desnoetrte that theve Mesied paramnsters ste
‘ly eceoetacve of actual able condi sa fra iter pacing
ard dicteiie cana ete concected. "Than energie a ample talaga,
Dazed en ea3y-o-nake loetocueacy messuremcns or quantitative ev
ati of dose te> ‘mparant cable per parametee. Applications af the
651 rer nr vir mRemueas youn, UL 1951

rath to conamerssl desyes of anlipaved eae are included. in shat
fellow

Li Penqrasey Tepoe=
‘he selfinducrance of pair af sright parse irs in eve pace ce
‘vthin any non maioetic del! fa ton ely ef the rao of conductor
Uinmeter ta the itera spacing i the fequeney ea aw that presi,
‘nshing ad akin elles are vegigibla, The forma as flows

sso ou Torri Stace

= 105g + 0108 toh) o

9 = terial srecing
8 conductor diameter

‘The fist teas gives the af fetanoe due to-net extemal Sanka:
aod the C1609 const: repens Euculage 3a she non megaetie

‘Some cectbooks give the fouls wita QS sa tie argument of the
logarithm Thistorm iso vi nadine sal compared to, ni he
‘er with cable pin, The divin of formal (in Rusell's“Altermating
{Caren Shon tha iyi or any 8, provi ony Chat she uments
tnurmly detsboted ace Cie wndtor erm ection

"While few elev that forma () wes valid for cable puis, 3,
1080 eps, was cdesable to esl espcineataly whetber or ret the
tistin the pity ed grate coming betwee pein, flected tie seasured
flvetaoe 21s fem in tis ange The eer of capliag betwen pas
fs green mba lof the cle pte earept the pair under test ane shore
together Lath eves othe cle, sus proving. arge number of cls
foore for any induced sural, Ea ming sberteny induccnce tests et
Ti ep na cog of 19 ngs cable wt UCR gmk eapcienas (i
ONB) it was Jn that opening or shorting the sustounding pate di not
Sie! the mesure vluctance. Azo, rounding ating the ar ead of the
test par ede rolfersnc, Te tats were peated wth the ume neulit
co ange rengng fom 20 tn SU.

sna be noted hytn corer diese met be all to Cs mage
tupeye indntance (Eto dain the tue earned inductance (1) when
the cae enti is euch that propagation eect bene appreciable. When
the correct tet inladed, Ve equation for L at 1060 eps beens

aE USI

where ZR ad ane esac induct, reilare, and mutual
rapacitant, mspecives
eases ATUTPATRED CARLES 655

bese feng only O56 for a of ON bt 3 So 300 of
{ecene type af cre The single cretion tam gen ol #fiinly
fccrte Jor age of CNH paar tan ant SM, ‘he spar
liming gt forse gang he ens it a HAR fo ge

Tis atio uss to allow fr seandingtahcup eects when corvertng
sua pr lng op le vals. Steading take ceed ste axe
shea im gt of gen pie compere to he i nth et Fle
renee a tae pa Sag the csbing operon. It depends opon Tae
soo of cable ad sraning ly andi egg for eabes of 30 mall gauge

fis ess causes en increase of 219% in pair eng over cable ength
fe ys in che outside lyse of fll ke CNB cable (2) ameter over
the paper wrapped ect)

‘Some short eng per with wie pall and approvimaely sight
sud with secunstely kno dtrensions mere male inthe bert.
True ase rei geet aL 1ONVcps Cte lus ageee very Casey wil
lncustansescalatel Soon forale (0), oe 2S zaiee em sbout 25,
‘rhids lose oo the nasal value for ible lt, up to neatly 030, which
"elise pestle value Thee rua howd Table. The 19 gauge
tut ad/28rashvol 20 gaat ined caztngestyender eomtant
fers. "Thece was ny seasurable cage fs neta for Cit Kats 39
Shot as 2", compsced with he sails, pacalll contin. Measuereat
sceuacy was cbou:=e0 2%,
et wre, sessane numsionL yormsa, yoLY 1951

he fog rests lx in he conan tha Ce eletive 4/28 ncn
slong the sof cable pale eas be determin inom fra 0 wsng
Wn cp ington, hs eceattey equ to al Ue inductance es
Suse d ie gewealy hoon ot ar be fou ith reatoe posi ram the
inductance, Sean tikes be fou wilt an aceurcy dependea the
Drecsion lhe hdustance teste Thi eonclsion applies reads o the
{spe of roduc elation However it soul be rote tratfanmal (1)
Srould no be acura if there hye ta be rragoticwetvialin ese
foci with the pai ver tes, uf nstnce, pi suru
om of sve le bouod cous

‘Tar Deezerise Uonetar

“The diesre cal pie eames of « ox-homogencous mistare of
soldi stevia and ai. The dsetsic constant of rable pecan
Bre dll a the ri of Fata asta capatzonee of the pal to the
ofa exacitance which woe est if she eel lating mace were
Temoved lug 100%; a lactis in the otrwine wlio cable
THenldon af cons, xl ent at te mates patance road Ye
with an ait diene, or with any other omozereoue diese of ks
Uiskeie constant eco Ue cmpleseorgiation ofthe cable sto
tase Ut nt cela

The shields lam pie ele o heres thee” pi) trace
son teeomponents of ran enclaves ae autated in Py, 1 Although
eee svt stature fier at ors thi of te ead pat bes
fentiy ie sane components of abitasl cniianee. Tle stacic sie
for the rable pie not nll a peter clindsea hut consis of he
bier ele pas of exesth wick are amccitely adjoant to che pair
Uiner srifracion, Te ret eapactaces other wines otis ground
trl ane very sey pl

ignoos metherket ruse have ban deriv by Mfrs, SP. Mend
bt tie Hol Pelesone Laboratories forthe raul eapactarce (Cena al
{he cere io grow (C) of hei! ae. These forks are yive
Appeilix 1. Far lcm parporen che can be oriten ae follows:

eo

®
rexscuumss ne uicrateeD cans

where ¢ = dlekeirc constant and fy and, a she faetinas defined ia
append
Diving equation (8) by equation (2

em Ai0) «
)

ay
‘Ags,
“Thus, the C.Co roto ie eleven of the decries, bein
2 Sui ony f he dmeona vi escibing the del i ong
nme atin 28 an npr in forma (1) "Tereor, kneels of
2, Cy and Cn fara eal pis sutton ts dimensional ratios
ata dice enatant, using the following pnocedae

1. Espn (1) tle! kr 28

2 Kain CC a 25, estan (Sesleri for SD.

5. Kosong Con 25, sal SD, exon (2) aelved fr

Cure sheets to fsiltate te olton f cuations (2 and (8) fr te ap
plik ges of 728 and $0 ane show gs. 2a 3

Whe shis save procedure ie apple io cable ye sing te rence
1000 eps Ly Cy snl Coy, hectic vont vale ein ely
squssenlative of the ae aeeonenve wih ane Felice of eee
fetent oly the he ad acual stvuctutes ave cube, Aa beens
‘fq in thie method oul be expected de od erences in configerston,
fn sun Hemogenety inthe ele cee

"The sents of Ee ero in the diestrc conta of a eable pr wen
eternity thissnetbod, was evaluate ly compan teats ae
having ¢ known, nesopeneoun dette with tos on an etal ede
ftroctre foving « nomotnepencoue aces but a hank dilectie

These vste were mde on a slat ong of eis alain tnenty-Loe
W.gioge pis "Pa condacors were insulted with sad plyetene. The
core wri wns pobethslene tape uer am elpeth eet Tow elu
‘eeht poletiplee compound krov ae DXL-1 has te same dieectre
Canes ell py hee [2.26 e vem fin = seal te
at ior ieeratee sel Mowe my al 150" Fabrenbet. Ty Eling he
termi airspace inthe cable nth DX 12 cae having a horogenceut
Aisle wk edhe nett of 22h idan. Vedic ti
Stent of tie cable stractare Tne lig ah DRT. Ue fons ome she
‘tio of mutual capacitance belere ander ling, snd elie om the
sccurcy of the ae as fers as apple to cle ys valle,
688 wren seston varmstens yooeuat, 1851

“Thm objectives wete not rele wih the hoped or Sues, borane af
itty esonntered i fling te iterate wea DCL. Hoth

Ci |
a i”
EE pc] 7)
JL
CHAT
rE 4 =

uijeue These penantages are based on Lar measured ipeense in exble
teight as. raul of dling with DXT-1, aud Che ait value elo ing a
Cult foo totaal inulcedeomducior and core ameter. Evidently
‘vrasmmarycons IN MULIMEARED EAR co)

the cable did sot fil comptes, because tall Les of either wir or
etayene 28 forme eng the ijt pres a weld act nach cut
2 coutinoal ow. Wale thee reals ate aot uf te uijvtive ny ae
oss encugh to be we

le i i

Fig, Cag 2 fete a 25, 8,

‘Te remaining ar fs the cable, oseupying inertial spre snl not
reiage the detec oma low tine uf pepe (228 in propor=
Si tthe prreneaze of ais velume This ig Beate tye Sete eld 3
weaker inthe Inert epsce han ia he apace laanaite'y sarang
Te conductor The elosticconesat af the espavineatal sae shoul,
heefne, be sewer 226 ar V+ (Oe of 128} = 2.17
6) en a ctear. yout, 200s 1951

“Table I shows the rents of aplication of ze ide! pir furnulas 2 1000
pe infurtinos and cepactaner mewatencats on the exerci cob
‘oth before antler ingen of DSC eoxaearé. The dvzctrs constant
oobenned fr the cable ein aes injection of DL f 220. This igre fs
‘thin Ie ins set fort resiuny, anf seme peakae that i a
ume lr itiouga thers eile way te make gn rn
eek i we arent 2.0 for he late conan! of he eable after iin
{HR DXtels tre telecoms to He unfilled wea codon em
be even Sie ony tye cir ais wa arene! 9 Eig Ch eae, the
Alri constant before ig given by

con = 200 DOR 18,
Wher: 90881 ffi, ~ Con Defoe ing

1070 ani, — Cog ing.

“Table I shes, hone, that epic af the Heal pie formals gives
186 Ee the normal deere comrant. HS Equo's 2% File daa the
Cornect Jl sive, Eaarsning te changes ip mural cyvlanee and
Coyucianee tu giouad whch oosrral lea the cable wae led wih
DML Lite seon that (ysreewed By 27.9% whereas Cas incense by
trly 204% The vest mata beswren wie « pet Co eraaed
thy anly 123% Since Cy fv a eomsponent of Con Bt WOE of iy his ace
uns ot ibe ower insta it Con 2 Pompaced ‘ith Cy, The ara
Sri in the cable afer fl ie sy sma. ican Be eacume! Ui the
fier fe substantially engenoous. nd the dictric bo Io
faneows Delon ilingy te parentage anges in Cy, Can abd Cy woe
fave beso eqn Tra is evident than ie sae endiion there
isa disectre coratak (ey) appenble for Cy eich i ie=aeon
We find that 6 i

Where (6.05 amis — Cy bor ine
(02080 ari ~ Cy ater ling

Vor given set of capastance wl udutence dat, there iy of coutey
ohprme valu cere costa: Whisk il shay he Hel pais fo.
trac This ate will be etuly tepeeenatve of scaleable cont
Tow if ao-homogeseily esate Non-homogensty, aa evidenced by the
aperenilly eterno inegeaty i go ty SCs for the 4