CROSSTALK IN COAXIAL CABLES 351 



+ LKiiPi + gi) - viK2(p2 + q2)ley-, (48) 



+ [ - 772i^i(pi + 5i) + ii:2(/'2 + g2)>>^ (49) 



In the section, of length /', adjacent to the far end of the energized 

 section, the impressed fields are zero and thus (under the condition that 

 e'l'i'' and e'>'2'' are large compared with unity), using primes to indicate 

 currents and voltages in this region, with the distance x\ taken positive 

 from X = /, 



// = a/g->i^' + -niai'e-y^^', (50) 



1 2 = riiai'e-y^'' + ai'e-^^^', (51) 



Vi' = Kxa^e--^^'' - yiiK^a^'e-y^^', (52) 



Fa' = - ViKiai'e-y^'' + K2a2'e-y^'''. (53) 



With tertiary 1 short-circuited, the boundary conditions to be 

 satisfied are that at x = x' = 0, Vi — Vi = and /o = A'. From 

 these boundary conditions, we obtain 



ai - — (pi + qi) H K^—r — i^ — » (54) 



«2 - — Kp2 -r 52) i v^^T — J^^ ' (55) 



Ai + r]i^K2 



The equal-level far-end far-end interaction crosstalk FF^ is given by * 

 FF, =||gT''J Ii'e-y^^'--'^dx'. (58) 



With 1 1 as given by equations (50), (56) and (57), under the restric- 

 tions we have placed on 71/' and 72/', we have 



FF. = ^' 



4Z(1 -77i7;2)(i^l + 7?i2ii:2) 



7) -^2(72 — 7) J L 7i — 7 72 — 7 



'niK2 . ViKi 



(59) 



< As pointed out in the Schelkunoff-Odarenko paper in the section on mutual 

 impedance, since a coaxial circuit is involved, the current distribution external to this 

 circuit does not affect the mutual impedance, and hence the current I2' contributes 

 nothing to the crosstalk. 



