JPS57210708A - Variable gain amplifier - Google Patents

Variable gain amplifier

Info

Publication number
JPS57210708A
JPS57210708A JP9524981A JP9524981A JPS57210708A JP S57210708 A JPS57210708 A JP S57210708A JP 9524981 A JP9524981 A JP 9524981A JP 9524981 A JP9524981 A JP 9524981A JP S57210708 A JPS57210708 A JP S57210708A
Authority
JP
Japan
Prior art keywords
capacitor
alpha
given
switch
input voltage
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
JP9524981A
Other languages
Japanese (ja)
Inventor
Takashi Sase
Kanman Hamada
Masahiro Ueno
Shoichi Furutoku
Kazuo Kato
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 JP9524981A priority Critical patent/JPS57210708A/en
Publication of JPS57210708A publication Critical patent/JPS57210708A/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
    • H03G1/0088—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal using discontinuously variable devices, e.g. switch-operated

Abstract

PURPOSE:To control the rate of a negative feedback accurately, by providing a switch for a negative feedback path and controlling the switching time of this switch. CONSTITUTION:An input voltag is given to a terminal 10 and a control pulse with time ratio alpha is applied to a terminal 60. When an FET switch 151 is turned on, a capacitor 131 only exists in the feedback path and the input voltage is given to an operational amplifier 200. In this case, a current flows to the capacitor 131. When the FET switch 151 is turned off, the feedback path consists of a parallel circuit of the capacitor 131 and a resistor and no input voltage is given to the operational amplifier 200. In this case, a current flows from the capacitor 131 to a resistor 111. The circuit is stable when the time product between the flowing-in and flowing-out current of the capacitor 131 is equal, and the output voltag is controlled to (1-alpha)/alpha times the input voltage with the time ratio alpha.
JP9524981A 1981-06-22 1981-06-22 Variable gain amplifier Pending JPS57210708A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9524981A JPS57210708A (en) 1981-06-22 1981-06-22 Variable gain amplifier

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9524981A JPS57210708A (en) 1981-06-22 1981-06-22 Variable gain amplifier

Publications (1)

Publication Number Publication Date
JPS57210708A true JPS57210708A (en) 1982-12-24

Family

ID=14132475

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9524981A Pending JPS57210708A (en) 1981-06-22 1981-06-22 Variable gain amplifier

Country Status (1)

Country Link
JP (1) JPS57210708A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62158922U (en) * 1986-03-28 1987-10-08

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4924337A (en) * 1972-06-27 1974-03-04
JPS55147816A (en) * 1979-05-09 1980-11-18 Hitachi Ltd Variable gain amplifier

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4924337A (en) * 1972-06-27 1974-03-04
JPS55147816A (en) * 1979-05-09 1980-11-18 Hitachi Ltd Variable gain amplifier

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62158922U (en) * 1986-03-28 1987-10-08
JPH0450646Y2 (en) * 1986-03-28 1992-11-30

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