US2265067A - Transmission system - Google Patents

Transmission system Download PDF

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Publication number
US2265067A
US2265067A US372977A US37297741A US2265067A US 2265067 A US2265067 A US 2265067A US 372977 A US372977 A US 372977A US 37297741 A US37297741 A US 37297741A US 2265067 A US2265067 A US 2265067A
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US
United States
Prior art keywords
section
line
currents
metallic
grounded
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
US372977A
Inventor
Irwin M Ellestad
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.)
AT&T Corp
Original Assignee
American Telephone and Telegraph Co Inc
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
Priority to BE442706D priority Critical patent/BE442706A/xx
Application filed by American Telephone and Telegraph Co Inc filed Critical American Telephone and Telegraph Co Inc
Priority to US372977A priority patent/US2265067A/en
Application granted granted Critical
Publication of US2265067A publication Critical patent/US2265067A/en
Priority to FR888196D priority patent/FR888196A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/28—Reducing interference caused by currents induced in cable sheathing or armouring
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/0123—Frequency selective two-port networks comprising distributed impedance elements together with lumped impedance elements
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H03H7/17—Structural details of sub-circuits of frequency selective networks
    • H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
    • H03H7/1758—Series LC in shunt or branch path
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/738—Interface circuits for coupling substations to external telephone lines
    • H04M1/74—Interface circuits for coupling substations to external telephone lines with means for reducing interference; with means for reducing effects due to line faults

Definitions

  • This invention relates to transmission systems and more particularly to a means for coupling together two or more sections of a transmission line wherein one of said sections is exposed to interference from neighboring power or communication lines.
  • This line may be composed of two sections, a metallic section 3 and a grounded section 4.
  • the metallic section and grounded section are connected together in the following manner.
  • a split-Winding repeat coil [4 is provided having its windings 5 connected to the tip and ring conductors of metallic section 3 and also having its windings connected to ground 8 through condensers 6 and 1.
  • the windings !2 of the repeat coil I4 are interconnected by condenser 13.
  • the upper winding is connected to the line of grounded section 4 and the lower winding connected to ground.
  • An impedance 9, which may be a repeat coil, is provided connected to the ring conductor of section 3 and the line of section 4.
  • a similar impedance coil I0 is connected to the tip conductor of section current.
  • the arrangements of the invention are particularly desirable for inter connecting a grounded section of line with a metallic section of line when the metallic section is exposed to inductive interference from a neighboring power line. Hence a portion of a power line H is shown in the vicinity of the metallic section 3 of the line.
  • the invention may be more fully understood from the following description of its operation.
  • the currents which are to be transmitted between the subscribers station I and the central OfllCB 2 include not only the voice currents but also alternating current for signaling and direct current for dialing purposes.
  • the location of the metallic section 3 in the vicinity of the power line II will cause so-called longitudinal currents to flow over the tip and ring conductors of the metallic section 3 as indicated by the arrows. These longitudinal currents might interfere with voice transmission and signaling or dialing on the line if connection were made in the usual manner between the metallic and grounded sections.
  • the windings 5 of the split-winding repeat coil l4 and condensers 6 and 1 have their constants so chosen that they constitute a low impedance shunt to ground for the longitudinal currents induced in the metallic section 3 due to its exposure to the neighboring power line H.
  • the impedances 9 and ID are so designed that they will have a high impedance to longitudinal currents and voice currents and a low impedance to direct Accordingly the longitudinal currents will neutralize each other in the windings 5 of repeat coil I4 and will not be repeated through coil l2 to the subscribers station I. They will not be transmitted through impedance 9 to station I. Direct current signals will be transmitted between the station I and the central office 2 through impedance 9. The voice currents will be transmitted in the normal manner through the transformer comprising repeat coils 5 and I 2.
  • a transmission line comprising a grounded section and a metallic section, a split winding repeating coil having two pairs of windings,
  • the first mentioned repeating coil windings and the circuit interconnecting them being adapted to constitute a low impedance shunt to ground for longitudinal currents induced in said metallic section, and an impedance coil connecting a conductor of said grounded section to a conductor of said metallic section, said last mentioned impedance coil having high impedance to longitudinal and voice currents and a 10 low impedance to direct currents.

Description

' Dec. 2, 1941.
l. M. ELLESTAD TRANSMISSION- SYSTEM Filed Jan. 3, 1941 INVENTOR Y E N m H A Patented Dec. 2, 194-1 TRANSMISSION SYSTEM Irwin M. Ellestad, Omaha, Nebr., assignor to American Telephone and Telegraph Company, a corporation of New York Application January 3, 1941, Serial No. 372,977
1 Claim.
This invention relates to transmission systems and more particularly to a means for coupling together two or more sections of a transmission line wherein one of said sections is exposed to interference from neighboring power or communication lines.
In telephone systems it is sometimes necessary to connect a metallic section of line with a grounded section of line. Sometimes the metallic section of the line will be located in the vicinity of a power line or other circuit and hence will be exposed to inductive interference from the power line or other circuit. The power line or other circuit may induce in the metallic section of the telephone line so-called longitudinal currents. These longitudinal currents, if transmitted from the metallic section of the line to the grounded section, would cause undesired interference with the proper functioning of the circuit. It is one of the objects of the invention to provide a means for coupling a metallic section of line, which is exposed to induction, to a grounded section of line in such a manner that induced longitudinal currents will not interfere with the proper functioning of the system, while at the same time allowing the normal transmission of voice currents and signal currents, including direct currents. Other objects and features of the invention will appear more fully from the detailed description thereof here- P inafter given.
The invention may be more fully understood from the following description together with the accompanying drawing in which is shown a circuit diagram embodying a preferred form of the invention.
In the drawing is shown a transmission line interconnecting a subscribers station I with a central office 2. This line may be composed of two sections, a metallic section 3 and a grounded section 4. The metallic section and grounded section are connected together in the following manner. A split-Winding repeat coil [4 is provided having its windings 5 connected to the tip and ring conductors of metallic section 3 and also having its windings connected to ground 8 through condensers 6 and 1. The windings !2 of the repeat coil I4 are interconnected by condenser 13. The upper winding is connected to the line of grounded section 4 and the lower winding connected to ground. An impedance 9, which may be a repeat coil, is provided connected to the ring conductor of section 3 and the line of section 4. A similar impedance coil I0 is connected to the tip conductor of section current.
3 and the grounded portion of section 4. As heretofore pointed out the arrangements of the invention are particularly desirable for inter connecting a grounded section of line with a metallic section of line when the metallic section is exposed to inductive interference from a neighboring power line. Hence a portion of a power line H is shown in the vicinity of the metallic section 3 of the line.
The invention may be more fully understood from the following description of its operation. The currents which are to be transmitted between the subscribers station I and the central OfllCB 2 include not only the voice currents but also alternating current for signaling and direct current for dialing purposes. The location of the metallic section 3 in the vicinity of the power line II will cause so-called longitudinal currents to flow over the tip and ring conductors of the metallic section 3 as indicated by the arrows. These longitudinal currents might interfere with voice transmission and signaling or dialing on the line if connection were made in the usual manner between the metallic and grounded sections. Accordingly the windings 5 of the split-winding repeat coil l4 and condensers 6 and 1 have their constants so chosen that they constitute a low impedance shunt to ground for the longitudinal currents induced in the metallic section 3 due to its exposure to the neighboring power line H. The impedances 9 and ID are so designed that they will have a high impedance to longitudinal currents and voice currents and a low impedance to direct Accordingly the longitudinal currents will neutralize each other in the windings 5 of repeat coil I4 and will not be repeated through coil l2 to the subscribers station I. They will not be transmitted through impedance 9 to station I. Direct current signals will be transmitted between the station I and the central office 2 through impedance 9. The voice currents will be transmitted in the normal manner through the transformer comprising repeat coils 5 and I 2.
While the invention has been disclosed as embodied in certain specific arrangements which are deemed desirable, it is understood that it is capable of embodiment in many and other widely varied forms without departing from the spirit of the invention as defined by the appended claim.
What is claimed is:
A transmission line comprising a grounded section and a metallic section, a split winding repeating coil having two pairs of windings,
another, the first mentioned repeating coil windings and the circuit interconnecting them being adapted to constitute a low impedance shunt to ground for longitudinal currents induced in said metallic section, and an impedance coil connecting a conductor of said grounded section to a conductor of said metallic section, said last mentioned impedance coil having high impedance to longitudinal and voice currents and a 10 low impedance to direct currents.
IRWIN M. ELLESTAD.
US372977A 1941-01-03 1941-01-03 Transmission system Expired - Lifetime US2265067A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE442706D BE442706A (en) 1941-01-03
US372977A US2265067A (en) 1941-01-03 1941-01-03 Transmission system
FR888196D FR888196A (en) 1941-01-03 1942-01-10 Electric wave transmission systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US372977A US2265067A (en) 1941-01-03 1941-01-03 Transmission system

Publications (1)

Publication Number Publication Date
US2265067A true US2265067A (en) 1941-12-02

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ID=23470414

Family Applications (1)

Application Number Title Priority Date Filing Date
US372977A Expired - Lifetime US2265067A (en) 1941-01-03 1941-01-03 Transmission system

Country Status (3)

Country Link
US (1) US2265067A (en)
BE (1) BE442706A (en)
FR (1) FR888196A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2754482A (en) * 1949-01-29 1956-07-10 Emi Ltd Band-pass circuit arrangements
US3731234A (en) * 1971-12-27 1973-05-01 Bell Telephone Labor Inc Combined voice frequency transmission and dc signaling circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2754482A (en) * 1949-01-29 1956-07-10 Emi Ltd Band-pass circuit arrangements
US3731234A (en) * 1971-12-27 1973-05-01 Bell Telephone Labor Inc Combined voice frequency transmission and dc signaling circuit

Also Published As

Publication number Publication date
FR888196A (en) 1943-12-06
BE442706A (en)

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