GB587370A - Improvements in or relating to arrangements for inverting the contrast of televisionsignals - Google Patents

Improvements in or relating to arrangements for inverting the contrast of televisionsignals

Info

Publication number
GB587370A
GB587370A GB2019044A GB2019044A GB587370A GB 587370 A GB587370 A GB 587370A GB 2019044 A GB2019044 A GB 2019044A GB 2019044 A GB2019044 A GB 2019044A GB 587370 A GB587370 A GB 587370A
Authority
GB
United Kingdom
Prior art keywords
amplifier
signals
control
picture
television
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
GB2019044A
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.)
THOMAS CAYTON NUTTALL
Cinema Television Ltd
Original Assignee
THOMAS CAYTON NUTTALL
Cinema Television 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 THOMAS CAYTON NUTTALL, Cinema Television Ltd filed Critical THOMAS CAYTON NUTTALL
Priority to GB2019044A priority Critical patent/GB587370A/en
Priority to FR937906D priority patent/FR937906A/en
Publication of GB587370A publication Critical patent/GB587370A/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
    • H04N5/20—Circuitry for controlling amplitude response
    • 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
    • H04N5/20—Circuitry for controlling amplitude response
    • H04N5/202—Gamma control

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Exposure Control For Cameras (AREA)
  • Television Receiver Circuits (AREA)

Abstract

587,370. Television. CINEMA-TELEVISION, Ltd., and NUTTALL, T. C. Oct. 18. 1944, No. 20190. [Class 40 (iii)] Signals derived by scanning a picture negative are inverted to produce a positive picture with correct contrast, in an arrangement including in cascade connection a logarithmic amplifier 2, which may be as described in Specification 514,401, an inverter stage 6 and an exponential amplifier 9. The repeater 4 between 2 and 6 which has a cathode load 5 and operates on the bottom bend of its characteristic provides for distortion corresponding to that represented by the " toe " of the Hand D curve of a photographic positive emulsion, the negative feedback straightening the characteristic as the current rises. Signals from amplifier 9 are fed through an inverter stage 11 to the picture reproducer 12. The valve 13 is pulsed with signals of mask waveform to drive valve 9 to anode current cut-off, this level representing " white " in the signals applied to 12. Amplifier 11 may thus be A.C. coupled and followed by a D.C. reinserting device 14. The controls afforded at 1, 5 and 10 correspond respectively to exposure control, control of development time, and control of light intensity in photography and may be graduated accordingly. Variation of bias 3 for stage 4 may be used instead of or as well as control 1, but this requires a wider range of operation in 2.
GB2019044A 1944-10-18 1944-10-18 Improvements in or relating to arrangements for inverting the contrast of televisionsignals Expired GB587370A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB2019044A GB587370A (en) 1944-10-18 1944-10-18 Improvements in or relating to arrangements for inverting the contrast of televisionsignals
FR937906D FR937906A (en) 1944-10-18 1946-12-24 Improvements to television and similar apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2019044A GB587370A (en) 1944-10-18 1944-10-18 Improvements in or relating to arrangements for inverting the contrast of televisionsignals

Publications (1)

Publication Number Publication Date
GB587370A true GB587370A (en) 1947-04-23

Family

ID=10141895

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2019044A Expired GB587370A (en) 1944-10-18 1944-10-18 Improvements in or relating to arrangements for inverting the contrast of televisionsignals

Country Status (2)

Country Link
FR (1) FR937906A (en)
GB (1) GB587370A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2172463A (en) * 1984-03-12 1986-09-17 Dunn Instr Inc Display for an image of normal or inverse polarity

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1106522B (en) * 1952-06-27 1961-05-10 Siemens Ag Method for increasing the fine contrast of images using an electro-optical image transmission device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2172463A (en) * 1984-03-12 1986-09-17 Dunn Instr Inc Display for an image of normal or inverse polarity
GB2172463B (en) * 1984-03-12 1989-07-19 Dunn Instr Inc Method and apparatus for controlling video display means for generating from a video signal normal or inverted images for photographing

Also Published As

Publication number Publication date
FR937906A (en) 1948-08-31

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