GB1423349A - Automatic gain control circuuits - Google Patents

Automatic gain control circuuits

Info

Publication number
GB1423349A
GB1423349A GB2247072A GB2247072A GB1423349A GB 1423349 A GB1423349 A GB 1423349A GB 2247072 A GB2247072 A GB 2247072A GB 2247072 A GB2247072 A GB 2247072A GB 1423349 A GB1423349 A GB 1423349A
Authority
GB
United Kingdom
Prior art keywords
capacitor
transistor
voltage
signal level
automatic 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.)
Expired
Application number
GB2247072A
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.)
Thorn Electrical Industries Ltd
Original Assignee
Thorn Electrical Industries 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 Thorn Electrical Industries Ltd filed Critical Thorn Electrical Industries Ltd
Priority to GB2247072A priority Critical patent/GB1423349A/en
Priority to DE19732323214 priority patent/DE2323214B2/en
Priority to SE7306598A priority patent/SE390687B/en
Priority to AU55622/73A priority patent/AU476158B2/en
Priority to JP5177373A priority patent/JPS5635068B2/ja
Publication of GB1423349A publication Critical patent/GB1423349A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H03G3/3052—Automatic control in amplifiers having semiconductor devices in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/52—Automatic gain control

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Control Of Amplification And Gain Control (AREA)
  • Television Receiver Circuits (AREA)
  • Circuits Of Receivers In General (AREA)
  • Amplifiers (AREA)

Abstract

1423349 Automatic gain control THORN ELECTRICAL INDUSTRIES Ltd 19 April 1973 [12 May 1972] 22470/72 Headings H3T and H4R An automatic gain control circuit for the video channel of a television receiver comprises a smoothing capacitor and means providing a relatively low resistance charge and discharge path for the capacitor under conditions of relatively rapid change in the signal level, but relatively higher resistance charge and discharge paths for the capacitor under substantially steady state conditions. A gain controlling voltage V IN is applied to the base of transistor TR1 and an .output control voltage V AGC is derived across capacitor C, being the collector potential VC of transistor TR1 plus the voltage drops in diode D1 and Zener diode D2: transistor TR2 is normally biased off. When the collector voltage VC falls, corresponding to a fall in signal level, the capacitor C rapidly discharges via diodes D1, D2 and transistor TR2 remains off. When the signal level rises, the collector voltage VC rises rapidly, being isolated from capacitor C by diodes D1, D2; transistor TR2 is then turned on and provides a path for the rapid charge of capacitor C. The arrangement is provided to deal with "aeroplane flutter".
GB2247072A 1972-05-12 1972-05-12 Automatic gain control circuuits Expired GB1423349A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB2247072A GB1423349A (en) 1972-05-12 1972-05-12 Automatic gain control circuuits
DE19732323214 DE2323214B2 (en) 1972-05-12 1973-05-09 Circuit arrangement for reducing hum interference in the gain control circuit of a picture IF amplifier for a television receiver
SE7306598A SE390687B (en) 1972-05-12 1973-05-10 COUPLING DEVICE FOR AUTOMATIC REINFORCEMENT CONTROL AT TELEVISION RECEIVER
AU55622/73A AU476158B2 (en) 1972-05-12 1973-05-11 Improvements in automatic gain control circuits
JP5177373A JPS5635068B2 (en) 1972-05-12 1973-05-11

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2247072A GB1423349A (en) 1972-05-12 1972-05-12 Automatic gain control circuuits

Publications (1)

Publication Number Publication Date
GB1423349A true GB1423349A (en) 1976-02-04

Family

ID=10179886

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2247072A Expired GB1423349A (en) 1972-05-12 1972-05-12 Automatic gain control circuuits

Country Status (5)

Country Link
JP (1) JPS5635068B2 (en)
AU (1) AU476158B2 (en)
DE (1) DE2323214B2 (en)
GB (1) GB1423349A (en)
SE (1) SE390687B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58119213A (en) * 1982-01-06 1983-07-15 Fujitsu Ten Ltd Amplifier
JPS60176314A (en) * 1984-02-21 1985-09-10 Rohm Co Ltd Automatic gain adjusting circuit
JPS63204916A (en) * 1987-02-20 1988-08-24 Sanyo Electric Co Ltd Rf agc circuit
TW200305346A (en) * 2002-04-12 2003-10-16 Nap Entpr Co Ltd Ear pad, and earphone with the pad

Also Published As

Publication number Publication date
DE2323214A1 (en) 1973-11-22
AU476158B2 (en) 1976-09-16
AU5562273A (en) 1974-11-14
SE390687B (en) 1977-01-03
JPS4962028A (en) 1974-06-15
DE2323214B2 (en) 1978-07-06
JPS5635068B2 (en) 1981-08-14

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee