[go: up one dir, main page]

JPS561649A - Conference telephone equipment - Google Patents

Conference telephone equipment

Info

Publication number
JPS561649A
JPS561649A JP7720579A JP7720579A JPS561649A JP S561649 A JPS561649 A JP S561649A JP 7720579 A JP7720579 A JP 7720579A JP 7720579 A JP7720579 A JP 7720579A JP S561649 A JPS561649 A JP S561649A
Authority
JP
Japan
Prior art keywords
circuit
output
room
equipment
compounder
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
JP7720579A
Other languages
Japanese (ja)
Inventor
Masamichi Ono
Atsuji Takeda
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
Original Assignee
NEC 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 Electric Co Ltd filed Critical NEC Corp
Priority to JP7720579A priority Critical patent/JPS561649A/en
Publication of JPS561649A publication Critical patent/JPS561649A/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

Landscapes

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

Abstract

PURPOSE:To realize the natural talking through the conference telephone without causing the howling and the talking head cut-off, by installing the detouring offset circuit between the aural switching circuit and the speaker/microphone. CONSTITUTION:The input/output of intra-room equipment 10 within conference room A is connected to switching circuit 80, sound offset circuit 70 and intra-room equipment 60 each in conference room B via sound offset circuit 20 and switching circuit 30 each. Circuit 20 calculates at 26 the transmission function of the detouring circuit between the speaker and the microphone of equipment 10 by the output of impulse generator 25 to then give the function to compounder 27. On the other hand, the signal received from room B via circuit 30 drives compounder 27. Then the output of compounder 27 is inverted at 28 to offset the output of equipment 10. At the same time, circuit 30 gives comparison at 34 to the levels between the transmission and reception signals and then gives the control to loss inserting unit 36 in accordance with the comparison output.
JP7720579A 1979-06-19 1979-06-19 Conference telephone equipment Pending JPS561649A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7720579A JPS561649A (en) 1979-06-19 1979-06-19 Conference telephone equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7720579A JPS561649A (en) 1979-06-19 1979-06-19 Conference telephone equipment

Publications (1)

Publication Number Publication Date
JPS561649A true JPS561649A (en) 1981-01-09

Family

ID=13627317

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7720579A Pending JPS561649A (en) 1979-06-19 1979-06-19 Conference telephone equipment

Country Status (1)

Country Link
JP (1) JPS561649A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57162592A (en) * 1981-03-31 1982-10-06 Nec Corp Echo preventing loudspeaking device
JPS6248844A (en) * 1985-08-28 1987-03-03 Rohm Co Ltd Acoustic coupling prevention circuit
WO1991012683A1 (en) * 1990-02-16 1991-08-22 Fujitsu Limited Speaking device having hand-free conversational function
JP2010178066A (en) * 2009-01-29 2010-08-12 Aiphone Co Ltd Intercom system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49121405A (en) * 1973-03-20 1974-11-20
JPS5217684A (en) * 1975-06-03 1977-02-09 Int Standard Electric Corp Method and apparatus for color marking on insulated conductor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49121405A (en) * 1973-03-20 1974-11-20
JPS5217684A (en) * 1975-06-03 1977-02-09 Int Standard Electric Corp Method and apparatus for color marking on insulated conductor

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57162592A (en) * 1981-03-31 1982-10-06 Nec Corp Echo preventing loudspeaking device
JPS6248844A (en) * 1985-08-28 1987-03-03 Rohm Co Ltd Acoustic coupling prevention circuit
WO1991012683A1 (en) * 1990-02-16 1991-08-22 Fujitsu Limited Speaking device having hand-free conversational function
US5479502A (en) * 1990-02-16 1995-12-26 Fujitsu Limited Speaking apparatus having handfree conversation function
JP2010178066A (en) * 2009-01-29 2010-08-12 Aiphone Co Ltd Intercom system

Similar Documents

Publication Publication Date Title
DK0412902T3 (en) Electroacoustic device for hearing impaired containing noise balancing
CA2186416A1 (en) Method and apparatus for multi-channel acoustic echo cancellation
ES8201387A1 (en) A direction- and frequency-independent loudspeaker- or microphone-column or a loudspeaker- or microphone-surface.
CA2061388A1 (en) Loudspeaker telephone device comprising a novel noise suppressing circuit
CA2014864A1 (en) Training method for an echo canceller for use in a voice conference system
WO1981002513A1 (en) Aid for curing or mitigating stammering
JPS561649A (en) Conference telephone equipment
FR2345872A1 (en) Video phonic equipment for conference - has camera and microphones with digital converter and switching unit
SE9501681D0 (en) telecommunications device
JPS5770000A (en) Stereo playback device
JPS54117612A (en) Mike remote control-system transceiver
JPS6429154A (en) Voice conference equipment
JPS56110400A (en) Stereo sound field expansion device
JPS5342721A (en) Head phone driver
JPS55147866A (en) Extension circuit of key telephone unit
JPS56117462A (en) Loudspeaking telephone device
JPS6424662A (en) Voice conference equipment
JPS6429153A (en) Voice conference equipment
JPS57176870A (en) Loud-speaking telephone set
JPS55137730A (en) Voice transmission/receiving unit utilizing ear-microphone
JPS5761367A (en) Branch coupling circuit for conference telephone
SU634482A1 (en) Voise-controlled telephone set
JPS5511673A (en) Automatic tone adjusting telephone set
GB666868A (en) Loudspeaking telephone system
JPS5627598A (en) Microphone