JPS6427325A - Echo canceller - Google Patents

Echo canceller

Info

Publication number
JPS6427325A
JPS6427325A JP18235787A JP18235787A JPS6427325A JP S6427325 A JPS6427325 A JP S6427325A JP 18235787 A JP18235787 A JP 18235787A JP 18235787 A JP18235787 A JP 18235787A JP S6427325 A JPS6427325 A JP S6427325A
Authority
JP
Japan
Prior art keywords
signal
noise
voice
correlation coefficient
circuit
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
JP18235787A
Other languages
Japanese (ja)
Inventor
Kaoru Yamamoto
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.)
Fujitsu Ltd
Original Assignee
Fujitsu 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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP18235787A priority Critical patent/JPS6427325A/en
Publication of JPS6427325A publication Critical patent/JPS6427325A/en
Pending legal-status Critical Current

Links

Landscapes

  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

PURPOSE:To improve the characteristic of an echo canceller by providing a correlation coefficient calculation section so as to obtain the correlation coefficient of a transmission side input signal from a 2-wire side to a 4-wire side, thereby deciding whether the signal is voice or noise and discriminating accurately the actual double talk state from the case with a large nearby noise. CONSTITUTION:A correlation coefficient calculation section 25 obtains a correlation coefficient of a transmission side input signal Sin outputted from a hybrid circuit 11 to a 4-wire side so as to decide whether the signal is voice or noise. When a double talk detection section 17 decides it as the double talk state, a deciding signal '1' is fed to a coefficient correction section 15 and an AND circuit 26. When the coefficient calculation section 25 decides noise, a noise deciding signal '1' is fed to an AND circuit 26. Thus, the attenuation of a variable attenuator 27 is increased by an output signal '1' of the AND circuit 26 and a transmission side output signal Sout is obtained, where the level of the echo residual signal including nearby end noise is reduced. Moreover, in case of the double talk state, when the section 25 decides voice, the attenuation of the variable attenuator 27 is kept zero, the voice signal is not attenuated but becomes the transmission side output signal Sout.
JP18235787A 1987-07-23 1987-07-23 Echo canceller Pending JPS6427325A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP18235787A JPS6427325A (en) 1987-07-23 1987-07-23 Echo canceller

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP18235787A JPS6427325A (en) 1987-07-23 1987-07-23 Echo canceller

Publications (1)

Publication Number Publication Date
JPS6427325A true JPS6427325A (en) 1989-01-30

Family

ID=16116900

Family Applications (1)

Application Number Title Priority Date Filing Date
JP18235787A Pending JPS6427325A (en) 1987-07-23 1987-07-23 Echo canceller

Country Status (1)

Country Link
JP (1) JPS6427325A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5193112A (en) * 1990-01-24 1993-03-09 Nec Corporation Arrangement and method for rapidly detecting double talk in long distance telephone communications system
US6445792B1 (en) 1996-04-25 2002-09-03 Mitsubishi Denki Kabushiki Kaisha Echo canceller for decreasing a deterioration factor of a speech quality
JP2007231581A (en) * 2006-02-28 2007-09-13 Nippon Steel & Sumikin Coated Sheet Corp Roof structure and method of constructing the same
JP2008219088A (en) * 2007-02-28 2008-09-18 Oki Electric Ind Co Ltd Echo canceler and echo cancellation method
US8208623B2 (en) 2006-11-21 2012-06-26 Fujitsu Limited Echo processing method and device

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5193112A (en) * 1990-01-24 1993-03-09 Nec Corporation Arrangement and method for rapidly detecting double talk in long distance telephone communications system
US6445792B1 (en) 1996-04-25 2002-09-03 Mitsubishi Denki Kabushiki Kaisha Echo canceller for decreasing a deterioration factor of a speech quality
JP2007231581A (en) * 2006-02-28 2007-09-13 Nippon Steel & Sumikin Coated Sheet Corp Roof structure and method of constructing the same
US8208623B2 (en) 2006-11-21 2012-06-26 Fujitsu Limited Echo processing method and device
JP2008219088A (en) * 2007-02-28 2008-09-18 Oki Electric Ind Co Ltd Echo canceler and echo cancellation method

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