JPS648755A - Conference communication equipment - Google Patents

Conference communication equipment

Info

Publication number
JPS648755A
JPS648755A JP16466887A JP16466887A JPS648755A JP S648755 A JPS648755 A JP S648755A JP 16466887 A JP16466887 A JP 16466887A JP 16466887 A JP16466887 A JP 16466887A JP S648755 A JPS648755 A JP S648755A
Authority
JP
Japan
Prior art keywords
echo
signal level
communication equipment
conference communication
turned
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
JP16466887A
Other languages
Japanese (ja)
Inventor
Taisuke Sasada
Yasuo Ito
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
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 filed Critical NEC Corp
Priority to JP16466887A priority Critical patent/JPS648755A/en
Publication of JPS648755A publication Critical patent/JPS648755A/en
Pending legal-status Critical Current

Links

Landscapes

  • Interconnected Communication Systems, Intercoms, And Interphones (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

PURPOSE:To prevent howling due to a rapid change in an echo path by performing training in response to the signal level of the input/output side of an echo canceller. CONSTITUTION:A level detection circuit 4 detects a signal level L1 at the input of the echo canceller 3, that is, before erasure of echo. The level detection circuit 6 detects a signal level L2 at the output side of the echo canceller, that is, after the erasure of echo. The quantity of the signal level is compared by a comparator 5, and in case of L1>=L2, a switch 7 connecting to a noise generation circuit 8 is turned off and in case of L1<L2, the switch is turned on to start the training. Thus, howling due to rapid change in the echo path is prevented.
JP16466887A 1987-06-30 1987-06-30 Conference communication equipment Pending JPS648755A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP16466887A JPS648755A (en) 1987-06-30 1987-06-30 Conference communication equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP16466887A JPS648755A (en) 1987-06-30 1987-06-30 Conference communication equipment

Publications (1)

Publication Number Publication Date
JPS648755A true JPS648755A (en) 1989-01-12

Family

ID=15797556

Family Applications (1)

Application Number Title Priority Date Filing Date
JP16466887A Pending JPS648755A (en) 1987-06-30 1987-06-30 Conference communication equipment

Country Status (1)

Country Link
JP (1) JPS648755A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04133437U (en) * 1991-05-31 1992-12-11 日本電気株式会社 Semiconductor device inspection equipment
US5621724A (en) * 1995-01-24 1997-04-15 Nec Corporation Echo cancelling device capable of coping with deterioration of acoustic echo condition in a short time

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04133437U (en) * 1991-05-31 1992-12-11 日本電気株式会社 Semiconductor device inspection equipment
US5621724A (en) * 1995-01-24 1997-04-15 Nec Corporation Echo cancelling device capable of coping with deterioration of acoustic echo condition in a short time

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