US3181087A - Hybrid transformer employing balancing resistors to increase isolation between loads - Google Patents

Hybrid transformer employing balancing resistors to increase isolation between loads Download PDF

Info

Publication number
US3181087A
US3181087A US105793A US10579361A US3181087A US 3181087 A US3181087 A US 3181087A US 105793 A US105793 A US 105793A US 10579361 A US10579361 A US 10579361A US 3181087 A US3181087 A US 3181087A
Authority
US
United States
Prior art keywords
fork
winding
resistors
windings
resistor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US105793A
Other languages
English (en)
Inventor
Almering Petrus Cornelis Maria
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
North American Philips Co Inc
Original Assignee
US Philips Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3181087A publication Critical patent/US3181087A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits
    • H04B1/54—Circuits using the same frequency for two directions of communication
    • H04B1/58—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/03—Hybrid circuits

Definitions

  • transformer forks are widely used for their particularly attractive electrical properties, since the relatively decoupled fork branches can be accurately adapted to the common fork branch, and no energy is dissipated in the fork itself during the transmission of signals.
  • Such forked transformers have, however, a complicated struc ture.' They may comprise, for example, five transformer windings with ten external connecting wires. Such structure require particular care in design and fabrication to satisfy the requirements of the forks.
  • resistor forks comprising resistors
  • this cornplicated structure of forked transformers is eliminated, but sinceresistor forks employ resistors, they have the serious disadvantage that an appreciable loss of energy occursin the transmission forks. This loss may amount, for example, to 10.7 db.
  • the invention has for its object to provide a transmission fork which is distinguished electrically and structurally from each of the. aforesaid transmission forks, and which is particularly suitable for the miniature structures desirable in transistor systems.
  • a transformer comprises two identical coupling windings, which are inductively coupled with a third winding connectedto the common fork branch.
  • the ends of the third winding comprise the connecting terminals for the common fork branch.
  • Corresponding ends of the two identical coupling windings are connected to each other by way of separate fork resistor.
  • the connecting terminals foreach of the, two decoupled fork branches comprise one end of one coupling winding and the end of the other coupling winding which is not connected the same fork resistor.
  • the resistances of these fork resistors are substantially equal Patent 0 Patented Apr. 27, 1965 ample, be used in'transistor-equipped line repeaters for carrier-wave telephone transmission.
  • the line repeater supplies a cable connected to the terminals 5, '6, and a measuring instrument is connected to the terminals 3, 4.
  • the figure illustrates the line repeater diagrammatically by the signal source 11, having a voltage 2E and by a series-connected resistor 12, which represents the internal resistance of the line repeater. at the terminals 3, 4, and 5, '6 (i.e. the measuring instrument and the cable respectively) are represented by the resistors 13 and 14 respectively.
  • the transformer 10 comprises, in accordance with the invention, two identical coupling windings 15, 16, which are inductively coupled with a winding 17,connected to the common fork branch 7.
  • the ends of winding 17 comprise the connecting ter-i minals 8, 9 for the common fork branch.
  • Corresponding ends of the two identical coupling windings 15, 16 are connected to each other by way of fork resistors 18 and 19 respectively.
  • the resistor19 is connected between the upper ends of windings 15 and 16, and the resistor 18 is connected between the lower ends of windings 15 and 16;
  • the connecting terminals 3, 4 and 5, 6 for the two decoupled fork branches 1, 2 are each formed by one end of one coupling winding 15 and the end of the coupling winding 16 which is not connected to the same fork resistor.
  • the resistances of resistors 18, 19 are being rendered substantially equal to the characteristic terminal impedances of the decoupled fork branches 1, 2.
  • Central tappings of the load'resistors 13 and 14 of this device may be connected simultaneouslyto ground without modification of the circuit.
  • the fork branches 1, 2 are loaded by load resistors 13 and 14 respectively, having resistances equal to the characteristic terminal impedances R, so that each of the resistors 18, 19, 13, 14 of the fork has the same value as the characteristic terminal impedance R.
  • Thesignal source 11 with the internal resistance 12 is matched to the. load formed by the transmission fork, so that the internal resistance 12 of the signal source 11 is equal to the load formed by the transmission fork. This may always be accomplished by a suitable choice of the transformation ratio between the Winding 17 and the two coupling windings 15, 16. If, for example, the internal resistance 12 of the signal source is /2. R, the transformato the characteristic terminalimpedances of the decoupled fork branches.
  • the transmission fork shown in the figure is of the balanced .typeand comprises two relatively decoupled fork branches 1, 2 with the associated connecting ter minals 3, 4 and 5, 6 respectively and a common fork branch 7 with the associated connecting terminals 8, 9.
  • the commonbranch is coupled to the two relatively decoupled fork branches 1, 2 by means of a transformer 10.
  • the transmission'fork of the figure mayffor exwill appear across the winding 17. Since the transformation ratio is 1:1:1, this voltage also appears across each at the coupling windings 15, 16.
  • the currents passing throughthe twoi coupling windings 15, 16 are identi-' cal, due to the symmetry of the transmission fork, and Since the total number of ampere turns of the transformer 10 is equal to zero the relationship between the currents I and the current I passing through the winding 17 is known. In the embodiment shown in which the'number of turns of the winding 17 and each of the two coupling windings 15, 16 is the same, it follows that: j
  • each, of the coupling windings 15, 16 will be traversed by a current I and the voltage across each of these coupling windings will be to 2E I R.
  • the loads BEST AVAILABLE COPY In spite of the use of the fork resistors 18, 19 in the transmission fork, no losses occur in the transmission fork in the above-described matched state, and the power fed by the signal source 11 to the transmission fork is divided equally between the load resistors 13, 14. This is evident from the following network analysis.
  • the variation of the current passing through the transmission fork may be defined in a simple manner. Assuming that the voltage across the coupling winding 15 produces a current I in the fork resistor 13 and the voltage across the coupling winding 1t: produces a current I in the fork resistor 19; the current through the load resistor 13 is designated by 1 In the figure the assumed directions of the various currents are indicated by the arrows.
  • the load resistors 13, 14 are relatively decoupled in an effective manner by proportioning each of the fork resistors 18 and 19 so as to be equal to the characteristic terminal impedance R of the fork. This means that a variation in load at the connecting terminals 3, 4 does not produce a current 4 variation at the connecting terminals 5, 6. If, for example, in the device shown one of the load resistors 13 or 14 is varied, equalization currents will flow through the fork resistors 18, 19 (as is evident from the Formulae I-IV with the given dimensions of the fork resistors 18, 19 equal to the characteristic terminal impedance R) so that the current passing through the other resistor 14 or 13 respectively and hence also the voltage across the resistors 14 and 13 respectively remains constant.
  • the transmission fork according to the invention has the important advantage, from an electrical standpoint, that the requirements for the forked transformer are materially simplified, since the parasitic trans,- former impedances which might affect the fork properties are found to be very low.
  • the particularly simple structure of the transformer which comprises only three windings with six connecting wires, renders this fork extremely suitable for the miniature structures actually used in transistor systems.
  • Winding 17 59 turns Winding 17 10 mh.
  • Coupling windings 15, 16 5 mh.
  • ferromagnetic core of the transformer 10 use is made of a cross-shaped core of the dimensions 14 X 20 X 20 mm. of ferroxcube, which material consists mainly of high-permeable, non-conductive ferrites, whereas the dimensions of the total transmission fork are 16 x 22.5 X 22.5 mm.
  • a two-wire line may be connected to the terminals 8 and 9
  • a transmitter branch and receiver branch may be connected to the terminals, 3, 4 or 5, 6 respectively.
  • An effective relative decoupling between the transmitter branch and the receiver branch is obtained in the manner described above.
  • a circuit for connecting a first two-wire line to second and third two-wire lines comprising a transformer having a first winding inductively coupled to second andthird windings, said second and third windings being identical to each other, means connecting third two-wire lines.
  • a circuit for connecting a second and third two-wire lines comprising a transformer having a first winding with first and second terminals, said first windings being inductively coupled to a second winding having third and fourth terminals and a third winding having fifth and sixth terminals, said second and third windings being identical to each other, means connecting said first two-wire line between said first and second terminal, a firstresistor connected between said third and fifthterminals', a sec- 0nd resistor connected between said fourth and sixth terminals, means connecting said second two-wire line between said third and sixth terminals, and means con meeting said third two wire line between said fourth and fifth terminals,,saidfirst and second resistors each having a value substantially equal to the characteristic impedance of said second and third two-wire lines.
  • a circuit for connecting a source of signals to first and second two-wire lines comprising a transformer having first, second and third inductively coupled windings, said second and third windings being identical to saidfirst winding to said first line, first and second re- 7 first two-wire line to BEST AVAILABLE COPY each other and having first and vsecond terminals, re-
  • third and fourth terminals respectively, means connecting said source to said first winding, first resistor means connected between said first and second terminals, second resistor means connected between said third and fourth terminals, means connecting said first two-wire line'between said first and fourth terminals,
  • said first and second resistor means each having a value substantially equal to the characteristic impedance of said two-wire'lines.
  • circuit of claim 3 comprising third and fourth resistors connected between said first and fourth, and second and third terminals, respectively, said third and fourthvresistors each having a value substantially equal to said characteristic impedance.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Dc Digital Transmission (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
US105793A 1960-05-21 1961-04-26 Hybrid transformer employing balancing resistors to increase isolation between loads Expired - Lifetime US3181087A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL251885 1960-05-21

Publications (1)

Publication Number Publication Date
US3181087A true US3181087A (en) 1965-04-27

Family

ID=19752367

Family Applications (1)

Application Number Title Priority Date Filing Date
US105793A Expired - Lifetime US3181087A (en) 1960-05-21 1961-04-26 Hybrid transformer employing balancing resistors to increase isolation between loads

Country Status (7)

Country Link
US (1) US3181087A (enrdf_load_stackoverflow)
CH (1) CH393437A (enrdf_load_stackoverflow)
DE (1) DE1153081B (enrdf_load_stackoverflow)
ES (1) ES267472A1 (enrdf_load_stackoverflow)
FR (1) FR1289315A (enrdf_load_stackoverflow)
GB (1) GB914838A (enrdf_load_stackoverflow)
NL (2) NL113982C (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3296557A (en) * 1963-12-09 1967-01-03 Westinghouse Electric Corp Hybrid network utilizing plural twowinding transformers and resistive balancing means
US3358247A (en) * 1965-04-08 1967-12-12 Bell Telephone Labor Inc Coupling circuit arrangement for the selective distribution of power
US3503016A (en) * 1968-08-28 1970-03-24 Adams Russel Co Inc Low frequency hybrid circuit having unbalanced parts
US4618952A (en) * 1983-11-04 1986-10-21 Fibronics Ltd. Communication of unipolar pulses
US4647868A (en) * 1985-03-25 1987-03-03 General Electric Company Push-pull radio-frequency power splitter/combiner apparatus
US4916410A (en) * 1989-05-01 1990-04-10 E-Systems, Inc. Hybrid-balun for splitting/combining RF power
US5097234A (en) * 1990-09-13 1992-03-17 Andresen Jack S Passive impedance matching device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2339338A (en) * 1998-05-30 2000-01-19 Electronic Tech Safety isolation transformer

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2035536A (en) * 1934-06-09 1936-03-31 American Telephone & Telegraph Interconnection of transmission lines
US2548397A (en) * 1945-05-26 1951-04-10 Baldwin Lima Hamilton Corp Apparatus for measuring and transmitting a condition from a rotatable member
GB749694A (en) * 1952-06-27 1956-05-30 Standard Telephones Cables Ltd Hybrid circuits for connecting a four wire transmission line to a two wire transmission line
US2909733A (en) * 1956-10-26 1959-10-20 Pintsch Electro G M B H Fa Hybrid circuit arrangement

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1062C (de) * 1877-07-23 Smith vacul'm Brake Company Limited London Vorrichtungen an Vacuura-Bremsen für Eisenbahnfahrzeuge

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2035536A (en) * 1934-06-09 1936-03-31 American Telephone & Telegraph Interconnection of transmission lines
US2548397A (en) * 1945-05-26 1951-04-10 Baldwin Lima Hamilton Corp Apparatus for measuring and transmitting a condition from a rotatable member
GB749694A (en) * 1952-06-27 1956-05-30 Standard Telephones Cables Ltd Hybrid circuits for connecting a four wire transmission line to a two wire transmission line
US2909733A (en) * 1956-10-26 1959-10-20 Pintsch Electro G M B H Fa Hybrid circuit arrangement

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3296557A (en) * 1963-12-09 1967-01-03 Westinghouse Electric Corp Hybrid network utilizing plural twowinding transformers and resistive balancing means
US3358247A (en) * 1965-04-08 1967-12-12 Bell Telephone Labor Inc Coupling circuit arrangement for the selective distribution of power
US3503016A (en) * 1968-08-28 1970-03-24 Adams Russel Co Inc Low frequency hybrid circuit having unbalanced parts
US4618952A (en) * 1983-11-04 1986-10-21 Fibronics Ltd. Communication of unipolar pulses
US4647868A (en) * 1985-03-25 1987-03-03 General Electric Company Push-pull radio-frequency power splitter/combiner apparatus
US4916410A (en) * 1989-05-01 1990-04-10 E-Systems, Inc. Hybrid-balun for splitting/combining RF power
US5097234A (en) * 1990-09-13 1992-03-17 Andresen Jack S Passive impedance matching device
WO1992005600A1 (en) * 1990-09-13 1992-04-02 Andresen Jack S Passive impedance matching device

Also Published As

Publication number Publication date
ES267472A1 (es) 1961-08-16
CH393437A (de) 1965-06-15
GB914838A (en) 1963-01-09
FR1289315A (fr) 1962-03-30
DE1153081B (de) 1963-08-22
NL113982C (enrdf_load_stackoverflow)
NL251885A (enrdf_load_stackoverflow)

Similar Documents

Publication Publication Date Title
US1762775A (en) Inductance device
US3731234A (en) Combined voice frequency transmission and dc signaling circuit
US3248673A (en) Double balanced transistor modulators
US3181087A (en) Hybrid transformer employing balancing resistors to increase isolation between loads
US3048798A (en) Directional coupler
US3311850A (en) Low loss hybrid connector utilizing high permeability magnetic core material
US3114120A (en) Radio frequency voltage balancing device
US4170761A (en) Remotely powered intermediate amplifier for communications transmission
US2629024A (en) Unbalanced-to-ground two-to-fourwire connection
US2742613A (en) Variable time delay system
US3934213A (en) Broad band directional coupling circuit
US3832647A (en) Signal distribution network
US2680218A (en) Audio transformer
US4419636A (en) Low frequency wide band signal coupler
US2204721A (en) Impedance network for coupling electric cable circuits
US2026308A (en) Balanced inductance device
US2685066A (en) Impedance inversion networks
US3566275A (en) Output splitting circuit using ferrite isolators and d-c feedthrough
US1759332A (en) Wave transmission circuit
US2875283A (en) Equivalent four-wire repeaters
US3296557A (en) Hybrid network utilizing plural twowinding transformers and resistive balancing means
US3355684A (en) Coaxial cable switch
US2235018A (en) Electric filter arrangement
US3904838A (en) Two-wire, bi-directional voice frequency repeater
US2771585A (en) Impedance transformer network