JPS55150605A - Variable gain amplifying circuit - Google Patents

Variable gain amplifying circuit

Info

Publication number
JPS55150605A
JPS55150605A JP5896179A JP5896179A JPS55150605A JP S55150605 A JPS55150605 A JP S55150605A JP 5896179 A JP5896179 A JP 5896179A JP 5896179 A JP5896179 A JP 5896179A JP S55150605 A JPS55150605 A JP S55150605A
Authority
JP
Japan
Prior art keywords
resistance
fet10
value
capacity
gain
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
JP5896179A
Other languages
Japanese (ja)
Inventor
Yasutomo Otake
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.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric 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 Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP5896179A priority Critical patent/JPS55150605A/en
Publication of JPS55150605A publication Critical patent/JPS55150605A/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
    • H03G1/0035—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal using continuously variable impedance elements
    • H03G1/007—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal using continuously variable impedance elements using FET type devices

Landscapes

  • Control Of Amplification And Gain Control (AREA)

Abstract

PURPOSE:To control the gain in a wide range while keeping the wide-band frequency characteristic, by adding and leading out output signals of noninversion and inversion amplfiers. CONSTITUTION:The minimum gain of transistor TR14 used in a noninversion amplifier becomes a value obtained by dividing the resistance value of resistance 13 by the parallel impedance of the off-impedance of FET10, which is a resistance change element, and resistance 9, and the gain of TR6 of an inversion amplifier becomes a value obtained by dividing the resistance value of resistance 13 by the parallel impedance of resistance 7 and capacity 8. Normally, since the off-resistance of FET10 is 10<6>OMEGA or more and can be ignored in comparison with the resistance value of resistance 9, values of resistances 7 and 9 are made equal to each other, and the value of capacity 8 is made equal to the capacity value between the drain and the source of FET10. Therefore, even if the voltage of input terminal 20 is raised and the resistance value of FET10 is lowered, the capacity between the drain and the source of FET10 is not changed, and a signal output amplitude approximately proportional reversely to resistance change of FET10 is obtained at output terminal 20. Consequently, the gain can be controlled in a wide range while keeping the wide-band frequency characteristic.
JP5896179A 1979-05-11 1979-05-11 Variable gain amplifying circuit Pending JPS55150605A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5896179A JPS55150605A (en) 1979-05-11 1979-05-11 Variable gain amplifying circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5896179A JPS55150605A (en) 1979-05-11 1979-05-11 Variable gain amplifying circuit

Publications (1)

Publication Number Publication Date
JPS55150605A true JPS55150605A (en) 1980-11-22

Family

ID=13099430

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5896179A Pending JPS55150605A (en) 1979-05-11 1979-05-11 Variable gain amplifying circuit

Country Status (1)

Country Link
JP (1) JPS55150605A (en)

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