US2129990A - Telephony - Google Patents

Telephony Download PDF

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Publication number
US2129990A
US2129990A US101669A US10166936A US2129990A US 2129990 A US2129990 A US 2129990A US 101669 A US101669 A US 101669A US 10166936 A US10166936 A US 10166936A US 2129990 A US2129990 A US 2129990A
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US
United States
Prior art keywords
impedance
impedances
supplementary
subscriber line
voltage
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
US101669A
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English (en)
Inventor
Fremery Frank De
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.)
Koninklijke Philips NV
Original Assignee
Philips Gloeilampenfabrieken NV
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 Philips Gloeilampenfabrieken NV filed Critical Philips Gloeilampenfabrieken NV
Application granted granted Critical
Publication of US2129990A publication Critical patent/US2129990A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/58—Anti-side-tone circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M9/00—Arrangements for interconnection not involving centralised switching
    • H04M9/08—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
    • H04M9/10—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic with switching of direction of transmission by voice frequency

Definitions

  • My invention relates to telephony and more particularly to duplex communication systems using a forked circuit arrangement.
  • Forked circuit arrangements are commonly used in duplex communication systems for connecting a. subscriber line to a transmitting channel and a receiving channel using a double line, such as the four-wire arrangement used in line telephony or in conference telephony.
  • these channels may'v also be constituted partly by wireless transmitting installations and my inVen tion includes such installations.
  • the object of my invention is to overcome the above diiiiculties and to provide a forked circuit system having back-coupling blocking means, which systemis completely free from back-coupling and does not employ line balances.
  • I provide the system with two additional impedances which form with the input impedance of the transmitting channel and with the output impedance of the receiving channel, a bridge arrangement havingv as a diagonal the subscriber line in series with another impedance.
  • the alternatingcurrents coming from the subscriber line produce equal and opposite voltages across the additional impedances, whereas the alternating currents coming from the receiving channel produce rectied'voltages across both of the additional impedances; the A. C. voltages across the impedance connection in series withV the subscriber line and those produced across the two additional impedances controlling the back-coupling barrier in opposite directions.
  • Figure 1 is a schematic Wiring diagram of a.
  • FIG. 1 is a schematic wiring diagram of the bridge arrangement used in Fig. 1.
  • the reference number I designates a conference room in which are 1ocated a microphone 2 and a loudspeaker 3 connected through a forked arrangement to the subscriber lines 8. and 9.
  • the loudspeaker 3 is connected through conductors 6 6, to an amplier e and ⁇ hence through conductor and an impedance I2 to the subscriber line B, and through conductor ⁇ 26 and an impedance II to point 24 connected 'to thesubscriber line 9.
  • microphone 2 is connected through conductors 'I- to an amplifier 5, and hence through a conductor 2l and the impedance I2 to the' subscriber line 8, and through conduc tor 28 and an impedance III to point 24.
  • the constructionA of such amplifiers is well known, detailed discussion of the same is believed unnece'ssary,
  • the system also includes a back-coupling sup- ⁇ pressor comprising a grid-controlled amplifying tube I3, and a relay I4 'whose actuating coil is connected in the anode circuit of tube I3 with one terminal connected to the plate of the tube and its other terminal connected through a battery 3l tothe cathode.
  • the relay I4 has a normally-open contact 20 adapted to shunt the lines 5 a-nd a normally-closed contact 2l' adapted toshunt the lines 1.
  • resistances I8 and I9 are connected in series across the grid and cathode of tube I3 respectively.
  • the resistance I8 is connected through a rectifier I6 to the secondary winding of a transformer 29 having a primary winding connected across the impedance I2.
  • resistance I9 is connected through a rectifier I'I to the secondary winding of a transformer 3Q Whose primary winding has its ends connected across impedances III and I I and its centertap connected to point 24.
  • ZS representing the inputl impedance of the transmitting circuit and Ze representing the output impedance of the receiving circuit, formV together with impedances I0 and II, a bridge arrangement having a diagonal comprising the series connection of the subscriber lines B and .9 and the impedance I2.
  • the impedances I0 and I I are given such Values that speech currentscoming from the subscriber lines 8, 9, will produce equal and opposite A. C. voltages in the impedances III and II, whereby no A. C. Voltage will be applied to rectifier I'I and hence will cause no voltage drop across resistance I9.
  • an A. C. voltage is produced across impedance I2 and applied to rectifier I6 to thereby produce a D. C. voltage drop across resist-Y ance I8.
  • the speech oscillations thereof are amplified by amplifier 5, reach the forked arrangement and produce an A. C. voltage across impedances IU, II and I2. appears from Fig. 2, the A. C. voltages across impedances I0 and II do not neutralize each other,
  • a duplex communication system comprising a subscriber line, a receiving channel and a transmitting channel connected to said subscriber line in a fork arrangement without the use of a line balance, a back-coupling suppressor for short-circuiting either the receiving or the transmitting channel, and means for controlling said back-coupling suppressor comprising an auxiliary impedance in series with the subscriber line and serving to produce a controlling voltage, a supplementary impedance in said receiving channel, a second supplementary impedance in said transmittingv channel.' said supplementary impedances being connected in series and serving to produce a controlling voltage, the alternating currents coming from the subscriber line producing equal and opposite voltages in said supplementary impedances, said supplementary impedances forming with the input impedance of the transmitting channel and the output impedance of the receiving channel a bridge arrangement having a diagonal comprising the subscriber line in series with said auxiliary impedance, means for rectifying the voltage produced across the auxiliary impedance to produce a rectied voltage whichV
  • a duplex communication system comprising a subscriber line, a receiving channel and a transmitting channel connected to said subscriber line in a fork arrangement without the use of a line balance, a back-coupling suppressor for short-circuiting either said receiving or transmitting channel, and means for controlling said back-coupling suppressor comprising an auxiliary impedance in series with the subscriber line and serving to produce a controlling voltage, a supplementary impedance in said receiving channel, and a second supplementary impedance in said transmitting channel, said supplementary impedances being connected in series and serving to produce a controlling voltage, the alternating currents coming from the subscriber line producing equal and opposite voltages in said supplementary impedances, and the alternating current coming from the receiving channel producing additive voltages in said supplementary impedances, said supplementary impedances forming with the input impedance of the transmitting channel and the output impedance of the receiving channel a bridge arrangement having a diagonal comprising the subscriber line in series with said auxiliary impedance, means for
  • a duplex communication system for conference telephony comprising a receiving channel, a subscriber line, a transmitting channel, said receiving and transmitting channels being connected to said subscriber line in a fork arrangement Without the use of a line balance, a back-coupling suppressor for short-circuiting either said receiving or transmitting channel comprising a grid-control tube, and a relay having an actuating coil connected in the plate circuit of said tube, and contacts in one position shunting said transmitting channel and in the other position shunting said receiving channel, and means for biasing the grid of said tube comprising an auxiliary impedance in said subscriber line, a supplementary impedance in said transmitting channel, a second supplementary impedance in said receiving channel, said supplementary impedances forming with the input impedance of the transmitting channel and with the output impedance of the receiving channel a, bridge arrangement having a diagonal comprising the subscriber line in series with the auxiliary impedance, two resistances connected in series in the grid circuit of said tube

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Interconnected Communication Systems, Intercoms, And Interphones (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Interface Circuits In Exchanges (AREA)
US101669A 1935-09-19 1936-09-19 Telephony Expired - Lifetime US2129990A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEN38630D DE665323C (de) 1935-09-19 1935-09-19 Mit Rueckkopplungssperre versehene Gabelschaltung

Publications (1)

Publication Number Publication Date
US2129990A true US2129990A (en) 1938-09-13

Family

ID=6540078

Family Applications (1)

Application Number Title Priority Date Filing Date
US101669A Expired - Lifetime US2129990A (en) 1935-09-19 1936-09-19 Telephony

Country Status (5)

Country Link
US (1) US2129990A (ja)
DE (1) DE665323C (ja)
FR (1) FR810646A (ja)
GB (1) GB463178A (ja)
NL (1) NL46308C (ja)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2531883A (en) * 1948-04-21 1950-11-28 Kaelin Pierre Substation circuit with loudspeaker
US2545477A (en) * 1947-05-29 1951-03-20 Levy Jacques Two-way loud-speaker intercommunication system
US2579571A (en) * 1947-03-13 1951-12-25 Westinghouse Electric Corp Communication apparatus
US2623949A (en) * 1949-06-08 1952-12-30 Le Teleampliphone Soc Two-way loud-speaker telephone installation
US2629024A (en) * 1950-12-29 1953-02-17 Bell Telephone Labor Inc Unbalanced-to-ground two-to-fourwire connection
US2694749A (en) * 1950-04-18 1954-11-16 Sepco 45 B D Sebastopol Communication system
US3041411A (en) * 1958-06-10 1962-06-26 Donald C Beatty Automatic, circuit-condition-change-responsive, on-off control for loudspeaking telephone and the like
US3046354A (en) * 1958-12-29 1962-07-24 Bell Telephone Labor Inc Loud speaking telephone
US3065300A (en) * 1958-09-30 1962-11-20 Modern Telephones Great Britai Loudspeaking telephone systems
US3075045A (en) * 1960-08-29 1963-01-22 Bell Telephone Labor Inc Speakerphone
US3189690A (en) * 1960-04-27 1965-06-15 Modern Telephones Great Britai Two-way telephone systems with talk-listen switching

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE976957C (de) * 1954-10-19 1965-03-11 Manfred Seiffert Einrichtung fuer elektrische Unterwassertelefonie

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2579571A (en) * 1947-03-13 1951-12-25 Westinghouse Electric Corp Communication apparatus
US2545477A (en) * 1947-05-29 1951-03-20 Levy Jacques Two-way loud-speaker intercommunication system
US2531883A (en) * 1948-04-21 1950-11-28 Kaelin Pierre Substation circuit with loudspeaker
US2623949A (en) * 1949-06-08 1952-12-30 Le Teleampliphone Soc Two-way loud-speaker telephone installation
US2694749A (en) * 1950-04-18 1954-11-16 Sepco 45 B D Sebastopol Communication system
US2629024A (en) * 1950-12-29 1953-02-17 Bell Telephone Labor Inc Unbalanced-to-ground two-to-fourwire connection
US3041411A (en) * 1958-06-10 1962-06-26 Donald C Beatty Automatic, circuit-condition-change-responsive, on-off control for loudspeaking telephone and the like
US3065300A (en) * 1958-09-30 1962-11-20 Modern Telephones Great Britai Loudspeaking telephone systems
US3046354A (en) * 1958-12-29 1962-07-24 Bell Telephone Labor Inc Loud speaking telephone
US3189690A (en) * 1960-04-27 1965-06-15 Modern Telephones Great Britai Two-way telephone systems with talk-listen switching
US3189691A (en) * 1960-04-27 1965-06-15 Modern Telephones Great Britai Two-way telephone systems with talk-listen switching
US3075045A (en) * 1960-08-29 1963-01-22 Bell Telephone Labor Inc Speakerphone

Also Published As

Publication number Publication date
NL46308C (ja)
FR810646A (fr) 1937-03-24
DE665323C (de) 1938-09-22
GB463178A (en) 1937-03-23

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