JPS58114554A - Howling preventing device - Google Patents

Howling preventing device

Info

Publication number
JPS58114554A
JPS58114554A JP20967181A JP20967181A JPS58114554A JP S58114554 A JPS58114554 A JP S58114554A JP 20967181 A JP20967181 A JP 20967181A JP 20967181 A JP20967181 A JP 20967181A JP S58114554 A JPS58114554 A JP S58114554A
Authority
JP
Grant status
Application
Patent type
Prior art keywords
delay time
signal
delay
howling
measuring
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
JP20967181A
Other versions
JPS634985B2 (en )
Inventor
Takashi Ogiwara
Original Assignee
Nec Corp
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

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M9/00Interconnection arrangements not involving centralised switching
    • H04M9/08Two-way loud-speaking telephone systems with means for suppressing echoes or otherwise conditioning for one or other direction of traffic
    • H04M9/082Two-way loud-speaking telephone systems with means for suppressing echoes or otherwise conditioning for one or other direction of traffic using echo cancellers

Abstract

PURPOSE:To prevent the howling in response to the fluctuation of delay time of an acoustic path, by measuring the delay time of sound waves between a speaker and a microphone, generating a pseudo audio signal based on the measurement and subtracting the signal from an input signal to the microphone. CONSTITUTION:A reception signal 22 inputted to a reception system input terminal 21 is branched partly and applied to a variable delay line 212 and given to a pseudo sound path 213 with a delay. This output is given to a subtractor 210, where a pseudo sound signal is subtracted from the signal inputted from a transmission system input terminal 28. The delay time at a variable delay line 212 is controlled with an output of a delay time measuring device 215. The measurement of the delay time is realized by providing an ultrasonic wave generator near a speaker 24, locating an ultrasonic wave receiver near a transmitter 27 and measuring the propagation time. Thus, since echo can be cancelled while correcting the delay time one after another, the howling can be prevented effectively.
JP20967181A 1981-12-28 1981-12-28 Expired JPS634985B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP20967181A JPS634985B2 (en) 1981-12-28 1981-12-28

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP20967181A JPS634985B2 (en) 1981-12-28 1981-12-28

Publications (2)

Publication Number Publication Date
JPS58114554A true true JPS58114554A (en) 1983-07-07
JPS634985B2 JPS634985B2 (en) 1988-02-01

Family

ID=16576671

Family Applications (1)

Application Number Title Priority Date Filing Date
JP20967181A Expired JPS634985B2 (en) 1981-12-28 1981-12-28

Country Status (1)

Country Link
JP (1) JPS634985B2 (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6041849A (en) * 1983-08-18 1985-03-05 Toshiba Corp Loudspeaker telephone set
JPS6248844A (en) * 1985-08-28 1987-03-03 Rohm Co Ltd Acoustic coupling prevention circuit
JPS6248843A (en) * 1985-08-28 1987-03-03 Rohm Co Ltd Acoustic coupling prevention circuit
JPS62157450A (en) * 1985-12-29 1987-07-13 Rohm Co Ltd Telephone set
JPS6348923A (en) * 1986-08-19 1988-03-01 Hitachi Ltd Echo canceller
JPS6429093A (en) * 1987-07-24 1989-01-31 Nippon Telegraph & Telephone Echo erasing device
US5259033A (en) * 1989-08-30 1993-11-02 Gn Danavox As Hearing aid having compensation for acoustic feedback
WO2008150022A1 (en) * 2007-06-08 2008-12-11 Sony Corporation Sound signal processor and delay time setting method
WO2018061956A1 (en) * 2016-09-30 2018-04-05 ヤマハ株式会社 Conversation assist apparatus and conversation assist method

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6041849A (en) * 1983-08-18 1985-03-05 Toshiba Corp Loudspeaker telephone set
JPS6248844A (en) * 1985-08-28 1987-03-03 Rohm Co Ltd Acoustic coupling prevention circuit
JPS6248843A (en) * 1985-08-28 1987-03-03 Rohm Co Ltd Acoustic coupling prevention circuit
JPS62157450A (en) * 1985-12-29 1987-07-13 Rohm Co Ltd Telephone set
JPS6348923A (en) * 1986-08-19 1988-03-01 Hitachi Ltd Echo canceller
JPS6429093A (en) * 1987-07-24 1989-01-31 Nippon Telegraph & Telephone Echo erasing device
US5259033A (en) * 1989-08-30 1993-11-02 Gn Danavox As Hearing aid having compensation for acoustic feedback
WO2008150022A1 (en) * 2007-06-08 2008-12-11 Sony Corporation Sound signal processor and delay time setting method
JP2008306535A (en) * 2007-06-08 2008-12-18 Sony Corp Audio signal processing apparatus, and delay time setting method
WO2018061956A1 (en) * 2016-09-30 2018-04-05 ヤマハ株式会社 Conversation assist apparatus and conversation assist method

Also Published As

Publication number Publication date Type
JPS634985B2 (en) 1988-02-01 grant

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