FR2251972A1 - Automatic gain control for television receiver - using signal referenced to black level avoids dependence on average brightness - Google Patents

Automatic gain control for television receiver - using signal referenced to black level avoids dependence on average brightness

Info

Publication number
FR2251972A1
FR2251972A1 FR7438094A FR7438094A FR2251972A1 FR 2251972 A1 FR2251972 A1 FR 2251972A1 FR 7438094 A FR7438094 A FR 7438094A FR 7438094 A FR7438094 A FR 7438094A FR 2251972 A1 FR2251972 A1 FR 2251972A1
Authority
FR
France
Prior art keywords
black level
average brightness
gain control
television receiver
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.)
Granted
Application number
FR7438094A
Other languages
French (fr)
Other versions
FR2251972B1 (en
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.)
Indesit Industria Elettrodomestici Italiana SpA
Original Assignee
Indesit Industria Elettrodomestici Italiana SpA
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 Indesit Industria Elettrodomestici Italiana SpA filed Critical Indesit Industria Elettrodomestici Italiana SpA
Publication of FR2251972A1 publication Critical patent/FR2251972A1/en
Application granted granted Critical
Publication of FR2251972B1 publication Critical patent/FR2251972B1/fr
Granted legal-status Critical Current

Links

Classifications

    • 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
    • H04N5/53—Keyed automatic gain control

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Television Systems (AREA)
  • Control Of Amplification And Gain Control (AREA)

Abstract

The system described overcomes the problems of an AGC signal derived from the average voltage level of picture plus synchronisation information which varies with the average brightness of the picture as well as with the strength of the signal received. This is achieved by deriving a signal dependant upon the relative amplitudes of the fixed black level and the periodic synchronisation signal, and amplifying this to apply to the receiver I.F. stages. The method is applicable only to signals in which the synchronisation is provided by a pulse occuring below the black level of the image information.
FR7438094A 1973-11-20 1974-11-20 Automatic gain control for television receiver - using signal referenced to black level avoids dependence on average brightness Granted FR2251972A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT7040373A IT999777B (en) 1973-11-20 1973-11-20 AUTOMATIC GAIN CONTROL SYSTEM

Publications (2)

Publication Number Publication Date
FR2251972A1 true FR2251972A1 (en) 1975-06-13
FR2251972B1 FR2251972B1 (en) 1982-04-16

Family

ID=11313863

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7438094A Granted FR2251972A1 (en) 1973-11-20 1974-11-20 Automatic gain control for television receiver - using signal referenced to black level avoids dependence on average brightness

Country Status (3)

Country Link
BE (1) BE822258A (en)
FR (1) FR2251972A1 (en)
IT (1) IT999777B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0601299A1 (en) * 1992-12-07 1994-06-15 Motorola, Inc. Circuit for use in positive modulation AGC systems

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0601299A1 (en) * 1992-12-07 1994-06-15 Motorola, Inc. Circuit for use in positive modulation AGC systems

Also Published As

Publication number Publication date
IT999777B (en) 1976-03-10
BE822258A (en) 1975-03-03
FR2251972B1 (en) 1982-04-16

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Legal Events

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TP Transmission of property