GB463178A - Improvements in telephone, radio and like communication systems - Google Patents

Improvements in telephone, radio and like communication systems

Info

Publication number
GB463178A
GB463178A GB25236/36A GB2523636A GB463178A GB 463178 A GB463178 A GB 463178A GB 25236/36 A GB25236/36 A GB 25236/36A GB 2523636 A GB2523636 A GB 2523636A GB 463178 A GB463178 A GB 463178A
Authority
GB
United Kingdom
Prior art keywords
impedances
voltage
over
channels
resistance
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
Application number
GB25236/36A
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
Publication of GB463178A publication Critical patent/GB463178A/en
Expired legal-status Critical Current

Links

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

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Interconnected Communication Systems, Intercoms, And Interphones (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

463,178. Two-way transmission. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Sept. 16, 1936, No. 25236. Convention date, Sept. 19, 1935. [Class 40 (iv)] A connecting circuit between a two-way line 8, 9 and transmitting and receiving channels 7, 6 with echo-suppressors comprises impedances 10, 11 in said channels forming a bridge circuit in conjunction with the output and input impedances Ze, Zs of the channels, the line 8, 9 together with a series impedance 12 forming a diagonal. A balancing network is not used. An echo-suppressing relay 14 normally operated to short-circuit the receiving channel 6 is controlled by valve 13 biassed by resistances 18, 19 across which D.C. voltages are built up by rectifiers 16, 17 connected across impedance 12 and impedances 10, 11. Incoming speech over the line results in a D.C. voltage across resistance 18, but not over resistance 19 since A.C. voltage over impedances 10, 11 oppose each other. The valve is thus negatively biassed .and relay 14 falls back to open the receiving channel 6 and block the transmitting channel 7. Speech over the transmitting channel results in A.C. voltage across impedance 12 and also a resultant voltage across impedances 10, 11, the consequent D.C. voltage over resistance 19 being such as to balance the negative bias over resistance 18 or even to make the bias more positive than normal. As shown, microphone 2 and loud-speaker 3 are situated in a conference room 1. The channels 6, 7 may include wireless links.
GB25236/36A 1935-09-19 1936-09-16 Improvements in telephone, radio and like communication systems Expired GB463178A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEN38630D DE665323C (en) 1935-09-19 1935-09-19 Hybrid circuit provided with feedback lock

Publications (1)

Publication Number Publication Date
GB463178A true GB463178A (en) 1937-03-23

Family

ID=6540078

Family Applications (1)

Application Number Title Priority Date Filing Date
GB25236/36A Expired GB463178A (en) 1935-09-19 1936-09-16 Improvements in telephone, radio and like communication systems

Country Status (5)

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

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE483501A (en) * 1947-03-13
FR1005063A (en) * 1947-05-29 1952-04-07 Device to avoid the feedback effect in loudspeaker telephone systems
CH271525A (en) * 1948-04-21 1950-10-31 Kaelin Pierre Station for sound transmission installation.
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
DE976957C (en) * 1954-10-19 1965-03-11 Manfred Seiffert Facility for electrical underwater telephony
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
NL125146C (en) * 1958-12-29
US3189690A (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
US2129990A (en) 1938-09-13
NL46308C (en)
DE665323C (en) 1938-09-22
FR810646A (en) 1937-03-24

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