JPS5489404A - Amplifier for telephone set - Google Patents

Amplifier for telephone set

Info

Publication number
JPS5489404A
JPS5489404A JP15765377A JP15765377A JPS5489404A JP S5489404 A JPS5489404 A JP S5489404A JP 15765377 A JP15765377 A JP 15765377A JP 15765377 A JP15765377 A JP 15765377A JP S5489404 A JPS5489404 A JP S5489404A
Authority
JP
Japan
Prior art keywords
amplifier
circuits
output
receiving
loss
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
JP15765377A
Other languages
Japanese (ja)
Other versions
JPS5622179B2 (en
Inventor
Kazuyoshi Fujiyoshi
Takaharu Murakami
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.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co 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 Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to JP15765377A priority Critical patent/JPS5489404A/en
Publication of JPS5489404A publication Critical patent/JPS5489404A/en
Publication of JPS5622179B2 publication Critical patent/JPS5622179B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M9/00—Arrangements for interconnection not involving centralised switching
    • H04M9/08—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)

Abstract

PURPOSE:To prevent howling by providing attenuator circuits after an amplifier, which amplifies the output of a microphone, and an amplifier, which amplifies receiving signals, respectively and oerating these attenuator circuits alternately at a transmission time and a receiving time. CONSTITUTION:Service loss circuit 3 is provided in the output side of transmission amplifier 1 which amplifies the output of microphone 2, and receiving loss circuit 4 is provided in the input side of rceiving amplifier 5 where receiving signals from the telephone line are inputted, and the output side of amplifier 5 is connected to speaker 6. Further, comparator 7 which controls loss circuits 3 and 4 to operate them alternately is provided, and transmission auxiliary loss circuit 9 and receiving auxiliary loss circuit 8 where output of amplifiers 1 and 5 are inputted through time constant circuits 11 and 10 are connected to this comparator 7, thereby making it possible to control loss circuits 3 and 4 by the control of comparator 7.
JP15765377A 1977-12-27 1977-12-27 Amplifier for telephone set Granted JPS5489404A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15765377A JPS5489404A (en) 1977-12-27 1977-12-27 Amplifier for telephone set

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15765377A JPS5489404A (en) 1977-12-27 1977-12-27 Amplifier for telephone set

Publications (2)

Publication Number Publication Date
JPS5489404A true JPS5489404A (en) 1979-07-16
JPS5622179B2 JPS5622179B2 (en) 1981-05-23

Family

ID=15654418

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15765377A Granted JPS5489404A (en) 1977-12-27 1977-12-27 Amplifier for telephone set

Country Status (1)

Country Link
JP (1) JPS5489404A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57139476U (en) * 1981-02-26 1982-08-31

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49106704A (en) * 1973-02-10 1974-10-09
JPS5220104U (en) * 1975-07-30 1977-02-14

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49106704A (en) * 1973-02-10 1974-10-09
JPS5220104U (en) * 1975-07-30 1977-02-14

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57139476U (en) * 1981-02-26 1982-08-31

Also Published As

Publication number Publication date
JPS5622179B2 (en) 1981-05-23

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