Communication Engineering
`
`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
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`MCGRAW-HILL BOOK COMPANY, iNC.
`
`New York
`
`Toronto
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`London
`
`1956
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`Exhii 1 HH
`
`AMX
`Exhibit 1032-00001
`
`

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`COMMUNICATION ENGINEERING
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`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
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`‘III HAP!-I PIE! COKPANY. YORK, PA.
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`AMX
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`Exhii 1 III!
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`AMX
`Exhibit 1032-00002
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`

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`1.
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`5-313. Phantom Circuits. =Any means by which the number
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`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.
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`1
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`9
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`’_',’
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`q_._.j
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`' Fro. 5-ll. Phantom telephone circuits.
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`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.
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`AMX
`Exhibit 1032-00003
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`

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`names NETWORKS
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`205
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`In order to make sure that the mrnfs 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
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`the
`in
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`F[(]_ 5.12_ Windingg of
`the two physicals, as well as between each
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`physical and the phantom.
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`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.
`Cables in which this is done are called
`“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.’f
`up
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`FIG- 5-13» TWO-Way telephone
`repeater which will not operate
`because of ,,singing_,,
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`v
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`AMX
`Exhibit 1032-00004
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`

`
`THE mrmrra LINE
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`297
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`Inasmuch as the outer conductor of the flexible coaxial cable is not a
`'; solid, continuous conducting sheet, the electric and magnetic fields may
`i not be confined to the region surrounded by the outer braid and leakage
`‘jfields may be present outside the cable, particularly at uhf and above.
`— }'This condition results from the incomplete shielding by the outer conduc-
`tor and may be minimized by adding a second grounded shield braid
`outside the cable. This results in a so-called “shielded coaxial cable.”
`’ 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 minimisecross talk that results
`3 from magnetic and capacitive coupling between adjacent pairs. The -
`., whole group of pairs is surrounded by a protective outer coating of lead
`‘or of corrugated aluminum covered with plastic. The telephone cable
`9' 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-
`érnission 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
`gwire pair is twisted and currents flow in opposite directions in the two
`,conductors comprising the pair, the flux linkages are so small that the
`"inductance per unit length, L, may be neglected in a number of calcula-
`Ktions. Furthermore, the paper serves as an excellent insulator so that
`G, the shunt conductance, is of neglible magnitude. The effect of neg-
`V_ lecting L and G in calculations for’ the telephone cable will be illustrated
`1 later in the chapter.
`‘I Cable and transmission-line manufacturers publish tables giving the
`Jour line parameters of their products. Typical values are listed in
`able 8-1. For simple line configurations, such as those of the parallel-
`e 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
`-n - e. The necessary equations may be derived by direct application
`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
`As: of a transmission line and the means of evaluating its components
`' ‘, L, G, and C have been covered in previous sections, it is now possible
`; I predict the behavior of a line when electrical signals are applied to it.
`9Using 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
`"line then exhibits series loop inductance L Ax, series loop resistance R Ax,
`V
`‘ See, for example, E. C. Jordan, " Electromagnetic Waves and Radiating Systems];
`an
`{Prentice-Hall, Inc., New York, 1950.
`
`'
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`AMX
`Exhibit 1032-00005
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`

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`AMX
`Exhibit 1032-00006
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`

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`-
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`-rnn mrmrrn: mm
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`299
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`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‘
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`_
`Gauze. Spacing.
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`Loop constantblmile .
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`12,o1um‘L,mh|
`Open-wire lines
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`104
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`165
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`12
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`I-1‘I-I3“.‘°!".°.°'.°5833585
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`Paper.-insulated
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`ii
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`191’
`161
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`191’
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`161
`or coaxial cable, dz - 0.375 in., d; - 0.1004 in.
`From Amer. Tel. and Tel. Co.
`A.W.G.
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`.‘~’.3.,I‘~‘~..3'*O0!-‘G
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`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-
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`fz
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`ZY(A:c)"Ai
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`Z_ R+jwL
`" Tic-:5‘
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`AMX
`Exhibit 1032-00007
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`

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`Tun 8-2. Lnu Pixuiirne Ion Pn.n.x.Ix.-wnl Lnn um.
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`8-0. Complex Propagation Constant. The complex propagation ~.--‘
`stent 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
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`_z./2+z.+z._ 5
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`""' “'“——z.
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`AMX
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`Exhii1HH:
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`AMX
`Exhibit 1032-00008