JPS573441A - Echo eliminator - Google Patents

Echo eliminator

Info

Publication number
JPS573441A
JPS573441A JP7693280A JP7693280A JPS573441A JP S573441 A JPS573441 A JP S573441A JP 7693280 A JP7693280 A JP 7693280A JP 7693280 A JP7693280 A JP 7693280A JP S573441 A JPS573441 A JP S573441A
Authority
JP
Japan
Prior art keywords
echo
circuit
line
terminal
transmission
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
JP7693280A
Other languages
Japanese (ja)
Inventor
Kenzo Takahashi
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.)
Nippon Telegraph and Telephone Corp
Original Assignee
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 Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Priority to JP7693280A priority Critical patent/JPS573441A/en
Publication of JPS573441A publication Critical patent/JPS573441A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
    • H04B3/23—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

PURPOSE:To simplify the device and to make the cost of device low, by detecting the propagated delay of echo between receiving and transmitting lines in 4-line transmission lines immediately before a call, forming a pseudo echo with the same amount, and eliminating the echo through canceling the both. CONSTITUTION:A measuring circuit 12 detects a ring back tone or MF signal inputted to an input terminal 3 connected to a receiving line of a 4-line transmission and inputs an isolated pulse to an input terminal 1 connected to a transmission line through an echo line from an output terminal 4, to measure the propagation delay time between them. Further, the set delay time of a timer 13 and a delay of a variable delay circuit 9 are decided and a filter coefficient of a filter coefficient circuit 14 is calculated at a control circuit 15. Further, a filter 10 outputs a pseudo echo with the filter coefficient by taking the output of the circuit 9 as the input after synthesis, and a subtractor circuit 11 inputs a transmission signal inputted to the terminal 1 and the pseudo echo, allowing to output the transmission signal only to a terminal 2 by canceling both the components of echo and pseudo echo.
JP7693280A 1980-06-06 1980-06-06 Echo eliminator Pending JPS573441A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7693280A JPS573441A (en) 1980-06-06 1980-06-06 Echo eliminator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7693280A JPS573441A (en) 1980-06-06 1980-06-06 Echo eliminator

Publications (1)

Publication Number Publication Date
JPS573441A true JPS573441A (en) 1982-01-08

Family

ID=13619492

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7693280A Pending JPS573441A (en) 1980-06-06 1980-06-06 Echo eliminator

Country Status (1)

Country Link
JP (1) JPS573441A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995031051A1 (en) * 1994-05-07 1995-11-16 Ntt Mobile Communications Network Inc. Echo canceler and its learning method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995031051A1 (en) * 1994-05-07 1995-11-16 Ntt Mobile Communications Network Inc. Echo canceler and its learning method
US6061444A (en) * 1994-05-07 2000-05-09 Ntt Mobile Communications Network, Inc. Echo canceler and method for learning for the same

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