US1834735A - Inductive artificial line - Google Patents

Inductive artificial line Download PDF

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Publication number
US1834735A
US1834735A US256571A US25657128A US1834735A US 1834735 A US1834735 A US 1834735A US 256571 A US256571 A US 256571A US 25657128 A US25657128 A US 25657128A US 1834735 A US1834735 A US 1834735A
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United States
Prior art keywords
inductance
cable
coil
artificial line
resistance
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Expired - Lifetime
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US256571A
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English (en)
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Pupin Michael Idvorsky
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Individual
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Individual
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Priority to US256571A priority Critical patent/US1834735A/en
Priority to GB23966/28A priority patent/GB306521A/en
Priority to DEC42679D priority patent/DE528830C/de
Priority to FR670232D priority patent/FR670232A/fr
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Publication of US1834735A publication Critical patent/US1834735A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/14—Two-way operation using the same type of signal, i.e. duplex
    • H04L5/1407—Artificial lines or their setting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/40—Artificial lines; Networks simulating a line of certain length

Definitions

  • FIG. 5 is a diagrammatic representation of FIG. 5.
  • the object of my invention is to provide an improved method for duplex transmission of'electrical signals over wave conductors, as for instance, over suboceanic cables.
  • duplex signalling over long submarine cables employs atthe transmitting station a local sectional wave conductor, the socalled artificialline, whichis placed on one side of a duplex bridge, the other side of the bridge containing the cable.
  • the electrical currents generated by the electrical pulses impressed upon the two sides of the bridge by a'local generator are split into two parts; one part is transmitted over the,
  • the cable and its balancing artificial line have the same terminal resistance and reactance for every frequency which 1s of 1mportance at the speed of signalling then they can be made to balance each other. It isobvious that when the local wave conductor-is an ordinary artificial line consisting of resistances in series and capacities in parallel then at higher speeds of signalling such a balance cannot be obtained, because such an artificial line is non inductive, whereas the cable has inductance the reaction of which becomes a determining factor-flat higher speeds. Inductance introduced into the artificial line Wlll not improve the balance, unless this inductance and its internal resistance vary with the frequency according to the same law as the average inductance and resistance of the cable elements. The process of formulating the rules for designing such an 1nduct1ve artificial line 1s d sclosed in this specification and it consists of two distinct mathematical formulae which guide the' design. 1'
  • the average eifecand resistance marine cable balanced "for duplex operation tive resistance and inductance of a submarine cable vary as though each were comprised oftwodistinct parts, one constant, and one varying with the frequency, and that the variable part'of the inductance decreases whereas the variable part of the resistance increases with the frequency of the impressed vary with the frequency of the impressed current in the same or, substantially the same manner as the average effective inductance go and resistance of a submarinecable vary.
  • This improved network furnishes therefore a means for accurately balancing a submarine cable over awide range of frequencies.
  • My invention comprises an inductive arti- .05 ficial line, preferably in the form of equal sections connected in series, the inductance. and resistance of each section of which vary in accordance with the laws which I have discovered and above described.
  • 1-70 In the drawings accompanying and forming part of this specification and in which like reference numerals designate correspending parts throughoutz- Fig. 1 is a diagrammatic representation by 7 curves A, B and C of the effective terminal reactances and resistances of a submarine cable and of. a balancing artificial line.
  • Fi g. 2 is a diagrammatic representation by curves A. and B of the effective inductances per nautical mile of the same cable. p 1
  • Fig. 3 diagrammatically represents the constructional elements of a sectionalartifi- 85 Icial line madein accordance With my invenytion;
  • Fig. 4 diagrammatically represents a subby means of my invention
  • Fig. 5 is a plan view of an air-cored coil of toroidal symmetry.
  • Fig. 6 shows an end view of the same.
  • Fig. 7 is a sectional view of the same taken on the line 77 of Fig. 6.
  • Fig. 8 is a sectional view of the coil shown in Figs. 5, G and 7 after an insulating compound has been poured around it.
  • Fig. 9 is a plan view of a nickel cored coil of toroidal symmetry.
  • Fig. 10 is a sectional view of the same taken on the line 10-10 of Fig. 9.
  • curves A and B represent at various frequencies the effective terminal resistance a and reactance b respectively, of an actual submarine cable which has the following constants:
  • curves A and B of Fig.2 were calculated by Equations
  • the latter curves, derived by calculation from experimental measurements give L and R and they represent graphically the law of variation of the average effective resistance and of the average effective inductance, respectively, per nautical mile ofthe cable. They furnish the data for the design of the inductive artificial line disclosed. by this invention. If, therefore, a sectional artificial line can be constructed in which the effective resistance and the effecsufficiently broad frequency interval the same or very nearly the same as in the cable then the two structures will have the same or very nearly the same terminal impedance for that frequency interval, and can balance each other in the duplex bridge.
  • the sectional artificial line described here is a structure of this kind as the following 1n athematical analysis will show. It is made up of preferably equal sections, each section having two inductance coils in series, one of which is shunted by a non-inductive resistance. At each point of uncture of two consecutive sections a condenser of suitable capacity is inserted between this point and the ground. Fig. 3 gives a graphical representation of one of these sections. The two inductance coils 3 and 4 are connected in series, coil 4 being shunted by a non-inductive resistance 7. Equal condensers and 6 are connected to points of juncture, 1 and 2, and to the ground through 8.
  • each of these sections be an equivalent of nautical miles of the cable; hence condensers 5 and 6 at the two terminals of the section will each have a capacity of 3.84 10" farads.
  • the total capacity of the artificial line should, preferably, be equal to the total capacity of the cable.
  • the length of one will then be an electrical equivalent to the length of the other.
  • inductance L we select proper values for R 'and R since g is a constant, which has a definite value assigned to itby experimental measurement.
  • the selection, hQWBVGIB lHHSiI cited that not only is Equation (9) satisfied, but also Equations (5),,(6), 7), and.
  • inductance L is fixed by the experimental measurements selected arbitrarily.
  • the method consists in attaching to the terminal of the artificial line a network of conductors which has the same impedan'ce for I the low frequencies as the network which is employed at the receiving end of the cable.
  • the numerals 1, 2, 3', etc. referto the apparatus' at one end of the cable, and 1', 2", 3, i
  • I I 1 denotes. the sending generator; 2, 3 de note two condensers in the two sides of the 'Wheatstone bridge, havingin one of its arms the cable 7 and in the other the] inductive artificial line described above and represented here by coils 11, 12, 13, 14, etc., and condensers 23, 24, 25, etc.
  • the artificial line and the" sending generator are connected as usual through socalled sea earths at 8 and 9 to "ground.
  • An impedance 5 is connected" in series with the cable 10 and serves to balance the impedance -which' the sea-earth 9 places inserie's with the inductive artificial line.
  • Numeral' tde notes the signal receiving apparatus;
  • At the end of the inductive artificial line is a variable capacity 29 anda variable resistanceBO by the adjustments of which their impedance is made approximately equal to the impedance of the network which connects the cable to ground at the receiving station.
  • the receiving apparatus in cross-arm 4 maybe any suitable curbing and amplifying system of conductoi's with local sources of energy supply.
  • the very object of this invention is, to innalling system described here.
  • the inductive artificial line described here has been. assumed to consist of equal sections, each section being equivalent to a cable length of 10 n. m. This assumption simplifies the explanation of the structure; it also simplifies its manufacture. But the wellknowii mathematical theory of sectional wave conductors makes it obvious that the sections may be much longer at signalling speeds of 600 letters per minute It is also obvious that the artificial line may be divided into groups of sections 1111Vl1l0l1 each section of one group represents a cable length of say 10 n. 111.; each section of the next group represents a cable length of 15 ii. 111.; and each section of the next group represents a cable length of 20 n. in. or even n. m.
  • the inductance coils used in the balancing network have a negligible external field. Otherwise they will have mutual inductance with external circuits and will. therefore be sensitive to external disturbances.
  • a toroidal coil is the simplest illustration of aclosed magnetic field of this kind, but there are other forms of coils with paramagnetic cores which have a negligibly small external field and therefore no mutual inductance with external circuits.
  • Another essential requirement is that the effective inductance and its accompanying effective resistance must not vary appreciably with the intensity of the signaling current.
  • Fig. 5 represents ten coils 31, 31, etc. wound upon ten wooden blocks 32, 32, etc.
  • Figs. 6 and 7 show these blocks with holes indicated by numerals 3. These holes permit the blocks to be slipped over a metal rod and clamped so as to form a rigid wooden rectangular pattern.
  • the ten blocks forming this pattern are permanently coupled by a flexible coupling consisting of a strip of linen indicated by theblack line 34 in Fig. 7 and by the dotted lines 34 in Fig. 5.
  • Coils 31, 31, etc, are then wound. by a machine and thus it is possible to make the individual coils equal to each other in every respect.
  • ⁇ Vhen all the ten coils have been wound the clamping rod is removed from the rectangular pattern and the ten coils, connected inseries and coupled to each other by the linen ribbon, are then distributed symmetrically around a circular wooden cylinder forming a single symmetrical coil consisting of a plurality of individual coils as represented in Figs. 5, 6 and 7.
  • a coil may be made to retain its form permanently by pouring around it an insulating compound made fluid by heat which hardens upon cooling.
  • Fig. 8 shows a cross-sectioinil view of the coil after'the insulating compound has been applied.
  • An air-cored coil of this con- L struction has no appreciable external magnetic field except at points in the immediate vicinity of the surface of the winding.
  • the insertion into this part of the magnetic field of a thin sheet of magnetic material like. silicon steel offers a means of a small adjustment of the inductance of the air-cored coil.
  • the air-cored coil acts like an ideal toroidal coil. Tts inductance and resistance do not vary with the strength of the signal- 1 ing current.
  • the inductance coil shown in detail in Figs. 5, (3. 7 and 8 is the inductance coil 3, Fig. 3: and 11. 13. 15, 17, etc., Fig. 4. It is an unshunted inductance coil, and h magnetically neutral core material as iiidicated above.
  • FIG. 9 is a top view and Fig. 10 represents the cross-secti on of the coil.
  • the plates are about 14 mils thick.
  • the external field of such a coil is vanishingly small.
  • This coil nor the air-cored coil have any mutual inductance with external circuits and, hence, no external electrical disturbances can afiect the circuit of such coils.
  • the nickel cored inductance coil is employed in every section of the inductive artificial line as a shunted inductance, the air-cored coil. being coils, the inductance of which shall not vary, V with the intensity offthe magnetizing force,
  • the nickel cored inductance coil shown in detail in Figs. *9 and 10 has a core of paramagnetic material whose permeability varies less with changing magnetizing forces than does that of iron,
  • he nickel cored coil being shunted by re sistance 7 receives a part, only, of the signaling current which passes through the air-cored coil, whereby the magnetizing force of this current upon the nickel core is diminished. It can be shown that if A be the amplitude of the signaling current passing through the winding 01 the air-cored coil and B the amplitude of the current which passes through the shunted winding of the nickel cored coil then to one section of the inductive artificial line. It. '?11l(lll0't21116 of the air-cored coil. 7
  • a balancing artificial line comprising a plurality of sections, each section containinga plurality of simple independent inductance coils connected in series, one at least of which is shunted by a non-inductive resistance elements I 3.
  • a-balancing artificial line comprising a plurality of sections, each section containing a plurality of simple independent inductance coils connected in series, one at least of which is shunted by a non-inductive re sistance, and shunt capacity elements.
  • a balancing artificial line comprising a plurality of sections, each section comprising a series arm and a shunt arm and containing in its series arm'two simple and independent inductance coils connected in series, one of which is shunted by a non-inductive resistance element, and containing initsshunt arm a capacity element.
  • the unshunted inductance coils have cores of neutral magnetic material and the shunted inductance coils have nickel cores.
  • each inductance coil has a closed magnetic circuit whereby its external magnetic field is minimized.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Geophysics And Detection Of Objects (AREA)
US256571A 1928-02-24 1928-02-24 Inductive artificial line Expired - Lifetime US1834735A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US256571A US1834735A (en) 1928-02-24 1928-02-24 Inductive artificial line
GB23966/28A GB306521A (en) 1928-02-24 1928-08-20 Improvements in artificial lines for telegraphy and like purposes
DEC42679D DE528830C (de) 1928-02-24 1929-02-22 Ausgleichsschaltung, welche zur Nachbildung eines Wellenleiters fuer ein gewaehltes Frequenzband dient und mehrere induktive Abschnitte aufweist
FR670232D FR670232A (fr) 1928-02-24 1929-02-23 Ligne artificielle inductive

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US306521XA 1928-02-24 1928-02-24
US256571A US1834735A (en) 1928-02-24 1928-02-24 Inductive artificial line

Publications (1)

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US1834735A true US1834735A (en) 1931-12-01

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US256571A Expired - Lifetime US1834735A (en) 1928-02-24 1928-02-24 Inductive artificial line

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US (1) US1834735A (de)
DE (1) DE528830C (de)
FR (1) FR670232A (de)
GB (1) GB306521A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9636262B2 (en) 2014-06-26 2017-05-02 The Procter & Gamble Company Method and apparatus for transferring a discrete substrate

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9636262B2 (en) 2014-06-26 2017-05-02 The Procter & Gamble Company Method and apparatus for transferring a discrete substrate

Also Published As

Publication number Publication date
DE528830C (de) 1931-07-07
FR670232A (fr) 1929-11-26
GB306521A (en) 1929-12-20

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