JPS5642462A - Automatic regulating circuit for signal level - Google Patents

Automatic regulating circuit for signal level

Info

Publication number
JPS5642462A
JPS5642462A JP11733979A JP11733979A JPS5642462A JP S5642462 A JPS5642462 A JP S5642462A JP 11733979 A JP11733979 A JP 11733979A JP 11733979 A JP11733979 A JP 11733979A JP S5642462 A JPS5642462 A JP S5642462A
Authority
JP
Japan
Prior art keywords
current
trq1
trq2
positive feedback
signal level
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
JP11733979A
Other languages
Japanese (ja)
Inventor
Yuji Tsuruga
Makoto Yoshitoshi
Yutaka Nishino
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.)
Iwatsu Electric Co Ltd
Nippon Telegraph and Telephone Corp
Original Assignee
Iwatsu Electric Co Ltd
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 Iwatsu Electric Co Ltd, Nippon Telegraph and Telephone Corp filed Critical Iwatsu Electric Co Ltd
Priority to JP11733979A priority Critical patent/JPS5642462A/en
Publication of JPS5642462A publication Critical patent/JPS5642462A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/738—Interface circuits for coupling substations to external telephone lines
    • H04M1/76—Compensating for differences in line impedance

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Control Of Amplification And Gain Control (AREA)

Abstract

PURPOSE:To regulate a signal automatically and stably by providing a switching circuit with a positive feedback loop by the line current detecting circuit of a telephone set and then by giving hysteresis characteristics to ON-OFF characteristics of switching. CONSTITUTION:When current I1 flowing from terminal C is small, switching transistor TRQ1 is OFF and TRQ2 is ON, so that total current I will be I1+I2, which is nearly equal to I1+I4. As current I1 increases so that I=ION, the voltage drop across resistance Rc reaches the threshold level of voltage VBE of TRQ1 to turn TRQ1 On and TRQ2 OFF and at the moment, current I5 is applied to resistance Rc via positive feedback loop (beta), so tat TRQ1 will further conduct. Even when current I1 decreases so that I=ION, positive feedback (beta) allows current I5 to flow, and consequently TRQ1 stays ON to further decrease current I1. The moment I=IOFF, TRQ1 turns OFF and TRQ2 turns ON, providing hysteresis characteristics. For this purpose, terminals A and B are connected to desired points to provide the automatic and stable adjustment of the signal level.
JP11733979A 1979-09-14 1979-09-14 Automatic regulating circuit for signal level Pending JPS5642462A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11733979A JPS5642462A (en) 1979-09-14 1979-09-14 Automatic regulating circuit for signal level

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11733979A JPS5642462A (en) 1979-09-14 1979-09-14 Automatic regulating circuit for signal level

Publications (1)

Publication Number Publication Date
JPS5642462A true JPS5642462A (en) 1981-04-20

Family

ID=14709255

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11733979A Pending JPS5642462A (en) 1979-09-14 1979-09-14 Automatic regulating circuit for signal level

Country Status (1)

Country Link
JP (1) JPS5642462A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61208951A (en) * 1985-03-13 1986-09-17 Sharp Corp Loudspeaker telephone set
US4926015A (en) * 1987-06-22 1990-05-15 Toyoda Gosei Co., Ltd. Liquid level sensor having a retained base plate

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61208951A (en) * 1985-03-13 1986-09-17 Sharp Corp Loudspeaker telephone set
US4926015A (en) * 1987-06-22 1990-05-15 Toyoda Gosei Co., Ltd. Liquid level sensor having a retained base plate

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