GB687568A - Improvements in or relating to circuits for focussing cathode ray beams - Google Patents

Improvements in or relating to circuits for focussing cathode ray beams

Info

Publication number
GB687568A
GB687568A GB1028849A GB1028849A GB687568A GB 687568 A GB687568 A GB 687568A GB 1028849 A GB1028849 A GB 1028849A GB 1028849 A GB1028849 A GB 1028849A GB 687568 A GB687568 A GB 687568A
Authority
GB
United Kingdom
Prior art keywords
focusing
line
focusing coil
electrostatic
coil
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
GB1028849A
Inventor
Eric William Bull
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.)
EMI Ltd
Electrical and Musical Industries Ltd
Original Assignee
EMI Ltd
Electrical and Musical 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 EMI Ltd, Electrical and Musical Industries Ltd filed Critical EMI Ltd
Priority to GB1028849A priority Critical patent/GB687568A/en
Publication of GB687568A publication Critical patent/GB687568A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
    • H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
    • H04N3/26—Modifications of scanning arrangements to improve focusing

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)

Abstract

687,568. Cathode-ray tubes. ELECTRIC & MUSICAL INDUSTRIES, Ltd. April 17, 1950, [April 16, 1949], No. 10288/49. Class 39(i) In cathode ray apparatus having a magnetic focusing coil and electro-magnetic deflecting means for scanning the beam over a screen at line and frame frequencies, symmetrical current waveforms at line and frame frequencies, preferably parabolic waveforms obtained by integrating the sawtooth deflection currents, are fed to the focusing coil or an auxiliary coil, so as to reduce the defocusing of the beam that arises due to the fringe action of the deflecting field where the beam emerges from the deflecting field. The focusing coil is connected to the anodes of a pair of valves and the line and frame scanning waveforms are each integrated by a resistance-shunt condenser combination and applied to the respective control grids of the valves the amplified outputs of which are applied to the focusing coil. The Provisional Specification states in addition that the deflecting means may be electrostatic. The focusing means may also be electrostatic in which case the compensating waveform is fed to one or more of the focusing electrodes or to a subsidiary electrostatic lens.
GB1028849A 1949-04-16 1949-04-16 Improvements in or relating to circuits for focussing cathode ray beams Expired GB687568A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1028849A GB687568A (en) 1949-04-16 1949-04-16 Improvements in or relating to circuits for focussing cathode ray beams

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1028849A GB687568A (en) 1949-04-16 1949-04-16 Improvements in or relating to circuits for focussing cathode ray beams

Publications (1)

Publication Number Publication Date
GB687568A true GB687568A (en) 1953-02-18

Family

ID=9965108

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1028849A Expired GB687568A (en) 1949-04-16 1949-04-16 Improvements in or relating to circuits for focussing cathode ray beams

Country Status (1)

Country Link
GB (1) GB687568A (en)

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