`
`W. L. EVERITT, Ph.D.
`
`Dean, College of Engineering
`University of Illinois
`
`G. E. ANNER, M.S. in Eng.
`
`Associate Professor of Electrical Engineering
`University of Illinois
`
`Tnmn Enrnon
`
`MCGRAW-HILL BOOK COMPANY, iNC.
`
`New York
`
`Toronto
`
`London
`
`1956
`
`‘.
`' A.
`. A-.;
`
`’
`
`.
`
`AMX and Dell, Inc.
`Exhii 1 HH
`
`AMX and Dell, Inc.
`Exhibit 1032-00001
`
`
`
`COMMUNICATION ENGINEERING
`
`Copyright © 1956 by tho Moflnw-Hill Book Company, Inc.
`
`Copyright, men, 1937, by the Mofluw-Hill Book Company, Inc.‘ Printed in
`t.heUnitod8tnzuofAmm-ion. Allrighunnarvod.
`'l'hisbook,ox-park
`thereof, mny not be reproduced in anyform without punnhinn oi the publhhon.
`
`Libmry ojccmgnu Catalog Can! Numbcr 55-12099
`n
`.
`
`‘III HAP!-I PIE! COKPANY. YORK, PA.
`
`~ I
`
`1.3,-vw
`'*«"-ta.g.ains...._-....:';—,
`
`.
`
`AMX and Dell, Inc.
`Exhii 1 III!
`
`AMX and Dell, Inc.
`Exhibit 1032-00002
`
`
`
`1.
`
`cornivurcamox nnarxaarunc
`V
`i
`"A
`5-313. Phantom Circuits. =Any means by which the number
`
`tends to reduce the relative cost of outside plant, a major ch
`longudistance transmission. An extremely simple method by
`can be done is the use of “phantom” circuits. A phantom circuit gives
`an additional telephone channel for each four wires, thereby increasing
`the carrying capacity 50, per cent.
`It works on a balancing principle
`similar to that of a bridge circuit. The terminal equipment required is
`very simple, consisting only of a pair of repeating coils (or transformers)
`at each end of the phantom. The connection is shown in Fig. 5-11.
`
`1
`
`9
`
`’_',’
`
`q_._.j
`
`' Fro. 5-ll. Phantom telephone circuits.
`
`The standard two-wire circuits are usually called “physical,” or “side,”
`circuits. The terminals of both physicals and phantoms are brought in
`to:-Jackson"-t_ke.long-distance board, so that the operator does not need to
`met It -‘phantom circuit any diflerently from a physical.
`By the principle‘ of' superposition the signals may be considered one at
`a time. T A-voltage impressed on the phantom circuit at the west end of
`Fig. 6-11 will cause a current to enter at the mid-tap of the secondary
`winding of each repeating coil.
`If the impedances of the two line wires
`of the physicals are equal to each other, the current will divide equally
`and so produce mmfs which cancel each other in each repeating coil.
`The currents due to the signal impressed on the phantom terminals will
`flow in the same direction in the two wires of physical 1 and in the oppo-
`site direction in the two wires of physical 2. At the far end the two
`currents will again produce equal and opposing mmfs in the repeating _
`coils, so that no flux will be produced. This absence of flux, due to the .
`-
`currents resulting from the phantom signal, prevents this signal from
`being transferred to the substations connected to the physicals.
`It also
`means that the effective inductance of the repeating coils is negligible
`for ‘phantom currents. Three conversations, one on each physical and
`one on the phantom, can therefore be carried on simultaneously without
`interference.
`The directions of the currents at some instant due to the several sig-
`0
`nalsare shown by the arrows in Fig. 5-11.
`
`AMX and Dell, Inc.
`Exhibit 1032-00003
`
`
`
`BRIDGE NETWORKS
`
`205
`
`In order to make sure that the minfs completely cancel each other, the
`leakage flux must be made negligible. This is accomplished by winding
`the two halves of the secondary winding with wires which are adjacent
`to each other, as illustrated in Fig. 5-12. Toroidal cores are also used to
`reduce leakage flux.
`It is extremely important that the impedances of the two sides of each
`physical line be made as nearly identical as possible.
`If this is not done,
`the phantom currents in the two sides will not be identical and so a mmf
`will be set up in the repeating coils. This
`will result in “cross talk,” or interference
`between the unbalanced physical and the
`phantom.
`If both physicals should be un-
`balanced, the phantom would provide a path
`so that cross talk could also occur between
`
`the
`in
`
`Fxa_ 5.12_ winding. of
`the two physicals, as well as between each
`"°P°“inB .00“!
`‘OF
`I189
`physical and the phantom.
`phmwm °"m""'
`The transmission on the phantom is actu-
`ally better than on the physicals. Since the phantom uses two wires in
`parallel for each conductor, the line impedance is cut in half.
`In order to prevent the currents flowing in one pair of wires in a cable
`from inducing a voltage in another pair, the pairs are twisted contin-
`\ uously along their length. On open-wire lines the two wires are trans-
`posed at regular intervals for the same purpose.
`When two pairs are phantomed, each
`’‘ pair individually must also be treated as
`\ __ Z
`a single conductor and the two pairs
`twisted with each other in a cable or trans-
`posed with each other on an open-wire line.
`FIG- 5-13- TWO-Way telephone
`’°P°‘“°" “'hi°.h Vi" “°‘ °P°"‘°° Cables in which this is done are called
`because of “singing.”
`“
`,
`.
`quadded ’ cables. Owing to the greater
`effective separation of the sides of a phantom circuit, its susceptibility to
`inductive interference is greater.
`5-14. Telephone Repeaters. One of the most important applications
`of a bridge balance is in the two-way repeater on telephone lines. As
`the length of a telephone circuit is increased, the line losses will reach a
`limit at which the transmission will no longer be commercially feasible.
`Beyond this point it is necessary to introduce amplification to make up
`for the line losses. The transmission of a telephone circuit should be the
`~ same in both directions. Therefore the amplifier must operate in both
`directions. The first idea which would occur to the experimenter is to
`connect two amplifiers side by side as shown in Fig. 5-13, one to operate
`in one direction and the second to amplify in the opposite direction. The
`_ circuit of Fig. 5-13 would not work, because it would oscillate, or ‘‘sing.’?
`\
`we
`
`AMX and Dell, Inc.
`Exhii 1 2-
`
`AMX and Dell, Inc.
`Exhibit 1032-00004
`
`
`
`mm mrmrra Inn:
`
`297
`
`Inasmuch as the outer conductor of the flexible coaxial cable is not a
`
`solid, continuous conducting sheet, the electric and magnetic fields may
`7' not be confined to the region surrounded by the outer braid and leakage
`,_. fields may be present outside the cable, particularly at uhf and above.
`‘This condition results from the incomplete shielding by the outer conduc-
`3- tor and may be minimized by adding a second grounded shield braid
`outside the cable. This results in a so-called “shielded coaxial cable.’’
`[1 The common telephone cable consists of a number of wire pairs,
`- insulated -with paper and twisted together. The several pairs are also
`«- twisted over the entire cable length to minirnisecross talk that results
`'3 from magnetic and capacitive coupling between adjacent pairs. The -
`x whole group of pairs is surrounded by a protective outer coating of lead
`3‘, or of corrugated aluminum covered with plastic. The telephone cable
`and other common transmission-line types are illustrated in Fig. 8-3.
`,
`8-8. Calculation of Line Parameters. While the concepts of the per
`‘unit length line parameters R, L, G, and C, were developed for the parallel-
`wire line, they are by no means peculiar to that configuration. All trans-
`mission lines exhibit all four of the line parameters to some extent, though
`_, in certain cases one or two of them may be of negligible magnitude.
`, This is notably demonstrated by the common telephone cable. Since each
`‘
`"wire pair is twisted and currents flow in opposite directions in the two
`‘fconductors comprising the pair, the flux linkages are so small that the
`[inductance per unit length, L, may be neglected in a number of calcula-
`ons. Furthermore, the paper serves as an excellent insulator so that
`, the shunt conductance, is of neglible magnitude. The effect of neg-"
`,
`‘fleeting L and G in calculations for‘ the telephone cable will be illustrated
`_',later in the chapter.
`" Cable and transmission-line manufacturers publish tables giving the
`};four line parameters of their products. Typical values are listed in
`; able 8-1. For simple line configurations, such as those of the parallel-
`;_wire or coaxial type, R, L, and C may be calculated from a knowledge of
`the line geometry and the properties of the materials from which they are
`u : e. The necessary equations may be derived by direct application
`{or field theory. They will not be derived‘ here but are summarized in
`able 8~2.
`V‘ 8-4. The Infinite Line, Z.. Since the equivalent circuit of a length
`of a transmission line and the means of evaluating its components
`‘J3, L, G, and C have been covered in previous sections, it is now possible
`predict the behavior of a line when electrical signals are applied to it.
`‘Using the equivalent-circuit idea, let the line be considered as being made
`:up of a large number of incremental lengths, A1. Each such length of
`:«
`flfine then exhibits series loop inductance L Ax, series loop resistance R Ax,
`~
`‘ See, for example, E. C. Jordan, "Electromagnetic Waves and Radiating Systems};
`Prentice-Hall, Iuc., New York, 1950.
`w
`an
`
`AMX and Dell, Inc.
`Exhii 1 2-
`
`AMX and Dell, Inc.
`Exhibit 1032-00005
`
`
`
`AMX and Dell, Inc.
`Exhibit 1032-00006
`
`
`
`-
`
`-rnn mrmrrn: mm
`
`299
`
`matter of convenience these elements may be arrangedin a sym-
`ncal T configuration so -that the entire line may be considered as the
`ting case as A9: —+ 0 of a" number of symmetrical T aectiomin cascade,
`T having the elements defined by Eqs. (8-3) and (8-4). On this
`. the results of Chap. 6 may be used to calculate the variation of
`Tau: 8-1‘
`
`_
`Gauze. Spacing.
`in.
`mils
`
`Loop constantblmile .
`'
`‘
`am ‘G,pmhos
`
`12,o1um‘L,mh|
`Open-wire lines
`
`. ..
`.
`.
`.
`.
`.
`. .
`T n-wire .
`n-wire phantom . .
`-wire .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`-wire . . . .
`.
`.
`.
`.
`.
`.
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`-wire phantom. .
`n-wire . . .
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`.
`.
`.
`. .
`
`104
`104
`104
`165
`165
`165
`
`12
`12
`18
`12
`12
`18
`
`I-1‘I-I3“.‘°!".°.°'.°5833585
`
`Paper.-insulated
`
`ii
`
`191’
`161
`. . .
`191’
`.\_.l
`161
`or coaxial cable, dz - 0.375 in., d; - 0.1004 in.
`From Amer. Tel. and Tel. Co.
`A.W.G.
`
`.‘~’.3.,I‘~‘~..3'*O0!-‘G
`
`y-state current and voltage along a uniform line, provided that it is
`an inated in Z.,. Expressions will first be derived for 7 and Z. in terms
`.—'the line constants. Then equations will be derived for voltage and
`' ent as a function of distance along the line.
`.
`'
`v-5. Characteristic Impedance. Corresponding to Z; of
`the sym-
`cal lumped iterative structure, one has Z An: for the line and, corre-
`
`fz
`
`ZY(A:c)"Ai
`
`Z_ R+jwL
`" Tic-:5‘
`
`AMX and Dell, Inc.
`Exhibit 1032-00007
`
`
`
`Tun 8-2. Lnu Pnnriirlu Ion Pn.n.x.Ix.-wnl Lnn um.
`CoA:nu.,Cnu
`‘
`
`Pnnllel-wire line:
`
`henryl/In
`?In;
`+
`jg» soszé
`
`dup to
`flux linkage:
`outside
`conductors
`
`-
`
`{nude/m
`
`.
`orocooh 5
`{undo/m
`
`for 0 > 57
`
`where u - dielectric permittivity
`3 KIQ
`o. - 10"‘/36: mks
`p. - conductor permeability
`' (II:-)dIo
`yu - dielectric permeability
`- (Mano
`no - 41 X lo" mks
`c - conductivity of oonducion
`
`8-0. Complex Propagation Constant. The complex propagation av‘
`stunt 1., for the equivalent section of length As may be obtained V
`similar manner. Applying Eq. (6-6) to the element of line of l" '
`As; one has
`-
`
`'
`
`y~- -1+2.z7:+,’§i(1+é{)
`
`AMX and Dell, Inc.
`Exhii1Hu:
`
`AMX and Dell, Inc.
`Exhibit 1032-00008