GB661807A - Television film scanning apparatus - Google Patents

Television film scanning apparatus

Info

Publication number
GB661807A
GB661807A GB1396649A GB1396649A GB661807A GB 661807 A GB661807 A GB 661807A GB 1396649 A GB1396649 A GB 1396649A GB 1396649 A GB1396649 A GB 1396649A GB 661807 A GB661807 A GB 661807A
Authority
GB
United Kingdom
Prior art keywords
film
level
projected
condenser
cathode
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
GB1396649A
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.)
Pye Electronic Products Ltd
Original Assignee
Pye 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 Pye Ltd filed Critical Pye Ltd
Priority to GB1396649A priority Critical patent/GB661807A/en
Publication of GB661807A publication Critical patent/GB661807A/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
    • H04N5/165—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level to maintain the black level constant

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Facsimiles In General (AREA)

Abstract

661,807. Television. COPE, J. E., THEILE, R., and PYE, Ltd. May 16, 1950 [May 25, 1949], No. 13966/49. Class 40 (iii). The D.C. level in a film television transmission system in which the film is projected intermittently on to a picture signal generating tube is controlled by means of voltage pulses generated in a photo-electric cell which is positioned so as to be illuminated during the intermittent projection periods. In the arrangement shown the pulses produced by the photoelectric cell P are fed to a cathode-follower valve VI, the output from the cathode of which is arranged to charge a condenser C via a switching circuit including diodes D1, D2 which are rendered conducting by means of voltage pulses e1, e2 during the periods when the film is projected on to the picture signal generating device F. The voltage across condenser C which is proportional to the D.C. level, i.e. to the average brightness of each projected film picture, is fed to a direct current amplifier V2 the output from which is employed to control the D.C. (i.e. block) level in a subsequent stage.
GB1396649A 1949-05-25 1949-05-25 Television film scanning apparatus Expired GB661807A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1396649A GB661807A (en) 1949-05-25 1949-05-25 Television film scanning apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1396649A GB661807A (en) 1949-05-25 1949-05-25 Television film scanning apparatus

Publications (1)

Publication Number Publication Date
GB661807A true GB661807A (en) 1951-11-28

Family

ID=10032606

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1396649A Expired GB661807A (en) 1949-05-25 1949-05-25 Television film scanning apparatus

Country Status (1)

Country Link
GB (1) GB661807A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2907821A (en) * 1956-01-19 1959-10-06 Marconi Wireless Telegraph Co Television apparatus
US2910531A (en) * 1954-11-30 1959-10-27 Thompson Ramo Wooldridge Inc Television circuit for obtaining stable set-up level
US3061671A (en) * 1959-11-16 1962-10-30 Servo Corp Of America Retrace signal eliminator

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2910531A (en) * 1954-11-30 1959-10-27 Thompson Ramo Wooldridge Inc Television circuit for obtaining stable set-up level
US2907821A (en) * 1956-01-19 1959-10-06 Marconi Wireless Telegraph Co Television apparatus
US3061671A (en) * 1959-11-16 1962-10-30 Servo Corp Of America Retrace signal eliminator

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