JPS5619235A - Ringing suppressing system using digital filter - Google Patents

Ringing suppressing system using digital filter

Info

Publication number
JPS5619235A
JPS5619235A JP9374779A JP9374779A JPS5619235A JP S5619235 A JPS5619235 A JP S5619235A JP 9374779 A JP9374779 A JP 9374779A JP 9374779 A JP9374779 A JP 9374779A JP S5619235 A JPS5619235 A JP S5619235A
Authority
JP
Japan
Prior art keywords
current
wire
digital filter
subscriber
ringing
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
JP9374779A
Other languages
Japanese (ja)
Other versions
JPS6214969B2 (en
Inventor
Kaoru Tokunaga
Kozo Kamata
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP9374779A priority Critical patent/JPS5619235A/en
Publication of JPS5619235A publication Critical patent/JPS5619235A/en
Publication of JPS6214969B2 publication Critical patent/JPS6214969B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits
    • H04B1/54—Circuits using the same frequency for two directions of communication
    • H04B1/58—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/03—Hybrid circuits

Landscapes

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

Abstract

PURPOSE:To attain the 2-wire/4-wire conversion of a low transmission loss for the time-division switchboard by varying the coefficient of the digital filter according to the detection value of the current fed to the subscriber telephone, thus ensuring an economical ringing suppression and then facilitating an easy maintenance control. CONSTITUTION:Both of the attenuation constant and the phase constant of the echo attenuation of the 2-wire/4-wire converter are in a simple relation with the length of the subscriber line. When the subscriber gives a call, the talking current flows to the telephone from talking current supply circuit 11 via subscriber line 2. Then, this feeding state is detected by current detecting circuit 12, and the filter coefficient of transmission digital filter 14 is varied by the result of the above current detection. Thus the cut-off frequency, the transmission loss of the filter or their characteristics are changed in order to prevent the ringing occurrence caused by the loop current. In this case, the simple balanced connection network 4 will do and in just one type.
JP9374779A 1979-07-25 1979-07-25 Ringing suppressing system using digital filter Granted JPS5619235A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9374779A JPS5619235A (en) 1979-07-25 1979-07-25 Ringing suppressing system using digital filter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9374779A JPS5619235A (en) 1979-07-25 1979-07-25 Ringing suppressing system using digital filter

Publications (2)

Publication Number Publication Date
JPS5619235A true JPS5619235A (en) 1981-02-23
JPS6214969B2 JPS6214969B2 (en) 1987-04-04

Family

ID=14091007

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9374779A Granted JPS5619235A (en) 1979-07-25 1979-07-25 Ringing suppressing system using digital filter

Country Status (1)

Country Link
JP (1) JPS5619235A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6408070B2 (en) * 1998-04-30 2002-06-18 Nortel Networks Limited Method and apparatus for echo control in a communication system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6408070B2 (en) * 1998-04-30 2002-06-18 Nortel Networks Limited Method and apparatus for echo control in a communication system

Also Published As

Publication number Publication date
JPS6214969B2 (en) 1987-04-04

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