JPS57143909A - Variable gain amplifying circuit - Google Patents

Variable gain amplifying circuit

Info

Publication number
JPS57143909A
JPS57143909A JP2915981A JP2915981A JPS57143909A JP S57143909 A JPS57143909 A JP S57143909A JP 2915981 A JP2915981 A JP 2915981A JP 2915981 A JP2915981 A JP 2915981A JP S57143909 A JPS57143909 A JP S57143909A
Authority
JP
Japan
Prior art keywords
trs
amplifying circuit
variable gain
bases
gain amplifying
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
JP2915981A
Other languages
Japanese (ja)
Inventor
Kazuo Yamaguchi
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.)
Fujitsu Ltd
Original Assignee
Fujitsu 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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP2915981A priority Critical patent/JPS57143909A/en
Publication of JPS57143909A publication Critical patent/JPS57143909A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G1/00—Details of arrangements for controlling amplification
    • H03G1/0005—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal
    • H03G1/0017—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal the device being at least one of the amplifying solid state elements of the amplifier
    • H03G1/0023—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal the device being at least one of the amplifying solid state elements of the amplifier in emitter-coupled or cascode amplifiers

Landscapes

  • Control Of Amplification And Gain Control (AREA)

Abstract

PURPOSE:To widen the band of a variable gain amplifying circuit used for an optical repeater, by powering up two differential couples of transistors (TR), exercising voltage control over the outputs of a differential couple of TRs, through a TR for compensating the variation of an operation point. CONSTITUTION:An input signal IN is applied to the bases of TRs Q6 and Q7 and an output signal OUT is obtained at the collectors of TRs Q8 and Q11 among differential couples of TRs Q8-Q11 connected to the collectors of the TRs Q6 and Q7; and a reference voltage Vr is applied to the bases of the TRs Q8 and Q11, a control voltage Va is applied to the bases of the TRs Q8 and Q10, and a bias voltage Vb is applied to the base of the TRQ12 as a current source. The emitter of a TRQ13 for compensating operation-point variation is connected to resistances (R) 4 and 5, the base is connected to collector connection points between the R7 and TRs Q9 and Q10, and the collector is connected to a power source. The resistance value of the R7 is set a half those of the Rs 4 and 5 to obtain a wide-band variable gain amplifying circuit suitable for IC- implementation.
JP2915981A 1981-02-28 1981-02-28 Variable gain amplifying circuit Pending JPS57143909A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2915981A JPS57143909A (en) 1981-02-28 1981-02-28 Variable gain amplifying circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2915981A JPS57143909A (en) 1981-02-28 1981-02-28 Variable gain amplifying circuit

Publications (1)

Publication Number Publication Date
JPS57143909A true JPS57143909A (en) 1982-09-06

Family

ID=12268475

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2915981A Pending JPS57143909A (en) 1981-02-28 1981-02-28 Variable gain amplifying circuit

Country Status (1)

Country Link
JP (1) JPS57143909A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60185411A (en) * 1984-03-02 1985-09-20 Fujitsu Ltd Gain variable amplifier circuit

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5384444A (en) * 1976-12-29 1978-07-25 Philips Nv Gain control signal amplifier

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5384444A (en) * 1976-12-29 1978-07-25 Philips Nv Gain control signal amplifier

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60185411A (en) * 1984-03-02 1985-09-20 Fujitsu Ltd Gain variable amplifier circuit

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