US2467494A - Device for reduction of cross talk between different lines at switches for distribution of programs - Google Patents

Device for reduction of cross talk between different lines at switches for distribution of programs Download PDF

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Publication number
US2467494A
US2467494A US737488A US73748847A US2467494A US 2467494 A US2467494 A US 2467494A US 737488 A US737488 A US 737488A US 73748847 A US73748847 A US 73748847A US 2467494 A US2467494 A US 2467494A
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US
United States
Prior art keywords
conductor
conductors
lines
programs
cross talk
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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
US737488A
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English (en)
Inventor
Peterson Nils Vilhelm
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.)
Telefonaktiebolaget LM Ericsson AB
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Telefonaktiebolaget LM Ericsson AB
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 Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
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Publication of US2467494A publication Critical patent/US2467494A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/65—Arrangements characterised by transmission systems for broadcast
    • H04H20/76—Wired systems
    • H04H20/82—Wired systems using signals not modulated onto a carrier
    • H04H20/83—Wired systems using signals not modulated onto a carrier not sharing the network with any other service
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/12—Arrangements for observation, testing or troubleshooting

Definitions

  • the present invention relates to a switching device for distribution of audio frequency programs, at which electric signals are distributed from a plurality of incoming lines to at least the same number selected from a plurality of outgoing lines.
  • the device is of that kind which consists of a contact field containing parallel conductors for one kind of lines and parallel conductors, crossing these conductors, for the other kind of lines. Communication between a line of one kind and a line of the other kind is produced by means of a Short-circuiting plug.
  • an electrically reflecting plate or grid arranged in a plane parallel to the conductors of the contact field and at a distance from these which is small in relation to the length of the conductors of the contact field, said plate suitably consisting of a metal sheet or metal grid connected to an electric zero-point.
  • the plate mainly covers the same area as the contact field.
  • an electrical image of currentcarrying conductors appears in the plate. This image reduce the influence of one circuit on another in the system, provided the plate be relatively near to the conductors. With such a plate the cross talk attenuation was increased to between 13 and 14 nepers, which lvalue indicates that a satisfactory protection for cross talk is obtained.
  • a number of line pairs l-5 has one conductor of each pair connected to a common conductor 2
  • the second conductor of each pair is connected to a contact strip or trolley wire, B-IO respectively, constituting the above mentioned parallel conductors for one kind of lines.
  • these conductors are in layers. These are crossed by a second layer of parallel conductors for the second kind of lines consisting of the contact strips or trolley wires [6-20 connected to one conductor of the pairs ll-l 5, respectively, the second conductor of 3 Claims. (01. 179-78 v 2 which is also connected to the common conductor 2
  • the ungrcunded conductor of line 3 is connected to the ungrounded conductor of line 13 and the ungrounded conductor of line 5 is connected to the ungrounded conductor of line 44 by means of short-circulting or connecting links $2 or suitable plugs connecting conductor 3 to conductor. l8 and conductor it to conductor I9.
  • a reflecting screen 23 is arranged, which suitably, by means of the conductcr 2d, is connected to the conductor 2 l, common to all the lines.
  • the expression screen is used to include a solid or perforated plate or grid, etc.
  • the conductors and contact strip of the lines 5-14 constitute a substantially closed loop enclosing a similar loop formed by the conductors and contact strips of the lines 3-I3.
  • These loops produce fields, partly common to each other, induced by the line currents, which produce considerable cross talk between the lines, in the absence of the reflecting plate.
  • the reflecting plate causes an essential reduction of the field due to the neutralizing efiect of the images.
  • the invention is naturally not limited to the construction shown in the figure, where the different lines have one conductor connected to a common conductor. It is also applicable if both conductors of the lines terminates in a contact field,
  • a switching device forthe transfer of audiofrequency signals from two or more of a plurality of incoming signal lines to two or more of a plurality of outgoing line comprising in combination; a conductor field composed of a layer of parallel conductors at least one of which is connected to each incoming signal line, a second and closely positioned parallel layer of parallel conductors crossing those of the first layer and having at least one connected to each outgoing signal line: connecting links joining selected ones of the first layer of conductors to selected ones of the second layer, and an electrically reflecting, grounded metal screen arranged parallel to said layers, at a distance from one of them which is small compared to the length of the conductors in said layers and of at least the same area as group of parallel conductors crossing those of the 15 first group and having each connected to one wire of each outgoing pair; a common conductor connecting all of the remaining wires of the incoming and outgoing pairs; connecting links selectively joining desired conductors of the first group to desired conductors of the second group; and an electrically reflecting metal screen connected to said common

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Communication Cables (AREA)
US737488A 1946-04-01 1947-03-27 Device for reduction of cross talk between different lines at switches for distribution of programs Expired - Lifetime US2467494A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE2467494X 1946-04-01

Publications (1)

Publication Number Publication Date
US2467494A true US2467494A (en) 1949-04-19

Family

ID=20425758

Family Applications (1)

Application Number Title Priority Date Filing Date
US737488A Expired - Lifetime US2467494A (en) 1946-04-01 1947-03-27 Device for reduction of cross talk between different lines at switches for distribution of programs

Country Status (2)

Country Link
US (1) US2467494A (forum.php)
BE (1) BE472232A (forum.php)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2412314A (en) * 1943-06-17 1946-12-10 Rca Corp High-frequency apparatus

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2412314A (en) * 1943-06-17 1946-12-10 Rca Corp High-frequency apparatus

Also Published As

Publication number Publication date
BE472232A (forum.php) 1947-04-30

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