GB1417982A - Gain control circuits - Google Patents

Gain control circuits

Info

Publication number
GB1417982A
GB1417982A GB449672A GB449672A GB1417982A GB 1417982 A GB1417982 A GB 1417982A GB 449672 A GB449672 A GB 449672A GB 449672 A GB449672 A GB 449672A GB 1417982 A GB1417982 A GB 1417982A
Authority
GB
United Kingdom
Prior art keywords
fet
gain control
amplifier
voltage
signal path
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.)
Expired
Application number
GB449672A
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.)
British Aircraft Corp Ltd
Original Assignee
British Aircraft Corp 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 British Aircraft Corp Ltd filed Critical British Aircraft Corp Ltd
Priority to GB449672A priority Critical patent/GB1417982A/en
Publication of GB1417982A publication Critical patent/GB1417982A/en
Expired 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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
    • H03G3/301—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers the gain being continuously variable
    • H03G3/3015—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers the gain being continuously variable using diodes or transistors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3036—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Amplifiers (AREA)

Abstract

1417982 Automatic gain control BRITISH AIRCRAFT CORP Ltd 9 April 1973 [31 Jan 1972] 4496/72 Heading H4R In a gain control system using a FET as the gain controlling element in a potentiometer in the signal path the FET is included in a closed loop feedback circuit which is incorporated in the gain control loop. As shown the a.g.c. control voltage at 1, is applied to the gate of the FET through a virtual earth amplifier, the output electrode of the FET is connected to the amplifier input to provide feedback and the FET source drain current is supplied from a constant current source I 1 , so that the resistance presented by the source drain path of the FET to the signal path is proportional to the a.g.c. control voltage. As shown the a.g.c. voltage is derived via a shaping network from the output of the video amplifier to provide the appropriate control law. The virtual earth amplifier may be an emitter coupled pair Tl, T2, Fig. 3 (not shown).
GB449672A 1972-01-31 1972-01-31 Gain control circuits Expired GB1417982A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB449672A GB1417982A (en) 1972-01-31 1972-01-31 Gain control circuits

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB449672A GB1417982A (en) 1972-01-31 1972-01-31 Gain control circuits

Publications (1)

Publication Number Publication Date
GB1417982A true GB1417982A (en) 1975-12-17

Family

ID=9778287

Family Applications (1)

Application Number Title Priority Date Filing Date
GB449672A Expired GB1417982A (en) 1972-01-31 1972-01-31 Gain control circuits

Country Status (1)

Country Link
GB (1) GB1417982A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4868519A (en) * 1988-11-02 1989-09-19 Dnic Brokerage Company Microprocessor-controlled amplifier
US4937466A (en) * 1988-09-29 1990-06-26 Ball Corporation Remote as signal attenuator
EP0398039A2 (en) * 1989-05-15 1990-11-22 Motorola, Inc. An attenuator circuit

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4937466A (en) * 1988-09-29 1990-06-26 Ball Corporation Remote as signal attenuator
US4868519A (en) * 1988-11-02 1989-09-19 Dnic Brokerage Company Microprocessor-controlled amplifier
EP0398039A2 (en) * 1989-05-15 1990-11-22 Motorola, Inc. An attenuator circuit
EP0398039A3 (en) * 1989-05-15 1991-08-21 Motorola, Inc. An attenuator circuit

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Legal Events

Date Code Title Description
PS Patent sealed
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee