JPS6424660A - Voice conference equipment - Google Patents

Voice conference equipment

Info

Publication number
JPS6424660A
JPS6424660A JP18144587A JP18144587A JPS6424660A JP S6424660 A JPS6424660 A JP S6424660A JP 18144587 A JP18144587 A JP 18144587A JP 18144587 A JP18144587 A JP 18144587A JP S6424660 A JPS6424660 A JP S6424660A
Authority
JP
Japan
Prior art keywords
attenuation
transmission
signal
line
echo
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.)
Granted
Application number
JP18144587A
Other languages
Japanese (ja)
Other versions
JP2573234B2 (en
Inventor
Hiroshi Oikawa
Shoji Makino
Masakazu Nishino
Takashi Saeki
Naohide Kushige
Shigenobu Minami
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.)
Toshiba Corp
Nippon Telegraph and Telephone Corp
Original Assignee
Toshiba Corp
Nippon Telegraph and Telephone 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
Application filed by Toshiba Corp, Nippon Telegraph and Telephone Corp filed Critical Toshiba Corp
Priority to JP62181445A priority Critical patent/JP2573234B2/en
Publication of JPS6424660A publication Critical patent/JPS6424660A/en
Application granted granted Critical
Publication of JP2573234B2 publication Critical patent/JP2573234B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Landscapes

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

Abstract

PURPOSE:To prevent a bypassed echo even when a sudden change in an echo path takes place by interposing an attenuation circuit respectively to a transmission line and a reception line of a speech signal path in series with an echo canceller and inserting a prescribed loss to the transmission line or the reception line if the signal level changes suddenly. CONSTITUTION:When the level of a cancel residual signal CS increases rapidly and exceeds a prescribed first threshold value, a control circuit 9 outputs an attenuation control signal LS to a voice switch attenuation circuit 8 to increase the attenuation value of a variable attenuator 8a inserted in the transmission signal path to a preset value. Thus, the residual signal is attenuated and the transmission of echo to a communication party is reduced. In the transfer to the transmission state, the attenuation of the variable attenuator 8a of the transmission signal path is restored zero and the attenuation of the variable attenuator 8b of the reception signal line is set to a prescribed value. Thus, even when the transmission state and the reception state are changed, howling is surely prevented.
JP62181445A 1987-07-21 1987-07-21 Audio conference equipment Expired - Lifetime JP2573234B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62181445A JP2573234B2 (en) 1987-07-21 1987-07-21 Audio conference equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62181445A JP2573234B2 (en) 1987-07-21 1987-07-21 Audio conference equipment

Publications (2)

Publication Number Publication Date
JPS6424660A true JPS6424660A (en) 1989-01-26
JP2573234B2 JP2573234B2 (en) 1997-01-22

Family

ID=16100894

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62181445A Expired - Lifetime JP2573234B2 (en) 1987-07-21 1987-07-21 Audio conference equipment

Country Status (1)

Country Link
JP (1) JP2573234B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114204954A (en) * 2020-08-28 2022-03-18 夏普株式会社 Wireless communication device, control method for wireless communication device, and electronic apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8229107B2 (en) 2006-01-17 2012-07-24 Mitsubishi Electric Corporation Echo canceler

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61172471A (en) * 1985-01-28 1986-08-04 Nec Corp Sneak preventing system of loudspeaker telephone set for conference telephone system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61172471A (en) * 1985-01-28 1986-08-04 Nec Corp Sneak preventing system of loudspeaker telephone set for conference telephone system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114204954A (en) * 2020-08-28 2022-03-18 夏普株式会社 Wireless communication device, control method for wireless communication device, and electronic apparatus

Also Published As

Publication number Publication date
JP2573234B2 (en) 1997-01-22

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