JPS57133755A - Branch coupling circuit for conference telephone set - Google Patents

Branch coupling circuit for conference telephone set

Info

Publication number
JPS57133755A
JPS57133755A JP1963381A JP1963381A JPS57133755A JP S57133755 A JPS57133755 A JP S57133755A JP 1963381 A JP1963381 A JP 1963381A JP 1963381 A JP1963381 A JP 1963381A JP S57133755 A JPS57133755 A JP S57133755A
Authority
JP
Japan
Prior art keywords
circuit
line
variable loss
loss
side variable
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.)
Pending
Application number
JP1963381A
Other languages
Japanese (ja)
Inventor
Hitoshi Fuda
Yoshiji Furuya
Haruo Ogura
Masaru Aoyanagi
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.)
NEC Corp
Nippon Telegraph and Telephone Corp
Original Assignee
NEC Corp
Nippon Telegraph and Telephone Corp
Nippon Electric Co Ltd
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 NEC Corp, Nippon Telegraph and Telephone Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP1963381A priority Critical patent/JPS57133755A/en
Publication of JPS57133755A publication Critical patent/JPS57133755A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities
    • H04M3/568—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities audio processing specific to telephonic conferencing, e.g. spatial distribution, mixing of participants
    • H04M3/569—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities audio processing specific to telephonic conferencing, e.g. spatial distribution, mixing of participants using the instant speaker's algorithm

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

PURPOSE:To eliminate squeak and to enable excellent communication, by comparing signal energy of each line through a detection a comparison control circuit and making the removal or insertion of a loss circuit based on the result. CONSTITUTION:A detection domparison control circuit 21 compares the signal energy on each line at each time and controls insertion/removal of a variable loss circuit. Through this operation, a loss determined with the number N of branches without fail at the input or output side of each line and the loop gain of 4- line part is constant. For example, an audio signal inputted to an input terminal 1 from a hybrid coil is greater than that of other lines, an input side variable loss circuit 5 and output side variable loss circuits 14, 15-16 are eliminated and input side variable loss circuits 6, 7-8 and output side variable loss circuit 13 are inserted by the circuit 21. Output is made to output terminals 18, 19-20 with 0dB and transmitted via a hybrid coil of other lines.
JP1963381A 1981-02-13 1981-02-13 Branch coupling circuit for conference telephone set Pending JPS57133755A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP1963381A JPS57133755A (en) 1981-02-13 1981-02-13 Branch coupling circuit for conference telephone set

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1963381A JPS57133755A (en) 1981-02-13 1981-02-13 Branch coupling circuit for conference telephone set

Publications (1)

Publication Number Publication Date
JPS57133755A true JPS57133755A (en) 1982-08-18

Family

ID=12004603

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1963381A Pending JPS57133755A (en) 1981-02-13 1981-02-13 Branch coupling circuit for conference telephone set

Country Status (1)

Country Link
JP (1) JPS57133755A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5913463A (en) * 1982-07-02 1984-01-24 エヌ・ベ−・フイリツプス・フル−イランペンフアブリケン 4-wired amplifier circuit for conference telephone
JPS603254A (en) * 1983-06-21 1985-01-09 Nec Corp Conference talking circuit
JPH0332266A (en) * 1989-06-29 1991-02-12 Nec Commun Syst Ltd Conference talking system
JPH03293849A (en) * 1990-04-11 1991-12-25 Toshiba Corp Key telephone unit

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5761367A (en) * 1980-09-30 1982-04-13 Nec Corp Branch coupling circuit for conference telephone

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5761367A (en) * 1980-09-30 1982-04-13 Nec Corp Branch coupling circuit for conference telephone

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5913463A (en) * 1982-07-02 1984-01-24 エヌ・ベ−・フイリツプス・フル−イランペンフアブリケン 4-wired amplifier circuit for conference telephone
JPH0336350B2 (en) * 1982-07-02 1991-05-31 Fuiritsupusu Furuuiranpenfuaburiken Nv
JPS603254A (en) * 1983-06-21 1985-01-09 Nec Corp Conference talking circuit
JPH0332266A (en) * 1989-06-29 1991-02-12 Nec Commun Syst Ltd Conference talking system
JPH03293849A (en) * 1990-04-11 1991-12-25 Toshiba Corp Key telephone unit

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