GB966616A - Improvements in television transmission systems - Google Patents

Improvements in television transmission systems

Info

Publication number
GB966616A
GB966616A GB4607961A GB4607961A GB966616A GB 966616 A GB966616 A GB 966616A GB 4607961 A GB4607961 A GB 4607961A GB 4607961 A GB4607961 A GB 4607961A GB 966616 A GB966616 A GB 966616A
Authority
GB
United Kingdom
Prior art keywords
transistor
capacitor
suppression period
frame
emitter
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
GB4607961A
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.)
Compagnie Francaise Thomson Houston SA
Original Assignee
Compagnie Francaise Thomson Houston SA
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 Compagnie Francaise Thomson Houston SA filed Critical Compagnie Francaise Thomson Houston SA
Publication of GB966616A publication Critical patent/GB966616A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/16—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level
    • H04N5/18—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level by means of "clamp" circuit operated by switching circuit
    • H04N5/185—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level by means of "clamp" circuit operated by switching circuit for the black level
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/222—Studio circuitry; Studio devices; Studio equipment
    • H04N5/253—Picture signal generating by scanning motion picture films or slide opaques, e.g. for telecine

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Television Receiver Circuits (AREA)
  • Picture Signal Circuits (AREA)
  • Processing Of Color Television Signals (AREA)

Abstract

966,616. Automatic gain control circuits. COMPAGNIE FRANCAISE THOMSONHOUSTON. Dec. 22, 1961 [Dec. 23, 1960], No. 46079/61. Heading H3T. In a television transmission system the peak white level is maintained constant by applying the amplified video signal to a quick-acting peak detector comprising diode 6 and series resistor 5, charging capacitor 6. At the beginning of every frame suppression period a second capacitor 12 of much smaller value is switched in parallel with the capacitor 7 by means of a switch comprising symmetrical transistor 14. It is disconnected before the end of the frame suppression period and the capacitor 7 is immediately discharged by means of a second switch comprising asymmetrical transistor 15, which is opened again preceding the end of the frame 'suppression period. The voltage across capacitor 12 is applied to a circuit of high impedance, comprising a transistor 16 in emitter-follower connection, the output of which is used to control the gain of a video amplifier or a circuit regulating the light intensity. The output of the emitter-follower 16 may include a phase advancing filter 17 which may also include a non-linear device. The switching transistors are operated by means of pulses; that for the transistor 15 may be derived by differentiation of the trailing edge of the pulse applied to the transistor 14.
GB4607961A 1960-12-23 1961-12-22 Improvements in television transmission systems Expired GB966616A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR847809A FR1284573A (en) 1960-12-23 1960-12-23 Improvements to television transmission systems

Publications (1)

Publication Number Publication Date
GB966616A true GB966616A (en) 1964-08-12

Family

ID=8745370

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4607961A Expired GB966616A (en) 1960-12-23 1961-12-22 Improvements in television transmission systems

Country Status (2)

Country Link
FR (1) FR1284573A (en)
GB (1) GB966616A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2007905A1 (en) * 1969-02-22 1970-11-05 Sony Corp., Tokio Device for automatic gain control for television cameras

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2007905A1 (en) * 1969-02-22 1970-11-05 Sony Corp., Tokio Device for automatic gain control for television cameras

Also Published As

Publication number Publication date
FR1284573A (en) 1962-02-16

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