GB1280877A - Line timebase circuit - Google Patents
Line timebase circuitInfo
- Publication number
- GB1280877A GB1280877A GB43840/69A GB4384069A GB1280877A GB 1280877 A GB1280877 A GB 1280877A GB 43840/69 A GB43840/69 A GB 43840/69A GB 4384069 A GB4384069 A GB 4384069A GB 1280877 A GB1280877 A GB 1280877A
- Authority
- GB
- United Kingdom
- Prior art keywords
- transistors
- halves
- deflection
- circuit
- supplied
- 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
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
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/16—Picture reproducers using cathode ray tubes
- H04N9/28—Arrangements for convergence or focusing
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Details Of Television Scanning (AREA)
- Video Image Reproduction Devices For Color Tv Systems (AREA)
- Dc-Dc Converters (AREA)
Abstract
1280877 Cathode-ray tube operating circuits; line time bar generators PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 4 Sept 1969 [7 Sept 1968 6 June 1969 8 July 1969] 43840/69 Headings H3T and H4T In a colour television display employing a single or plural beam cathode-ray tube "anisotropic" astigmatism produced by the beam deflecting coils which causes an electron beam having an elliptical or a circular cross-section to be given the form of a tilted (i.e. rotated) ellipse in the ease of single beam tubes and produces a "rotation" of the "triangular" landing points of the beams, in the case of three-beam tubes, such effects arising at the corners of the (rectangular) display, is corrected by forming the horizontal (line) deflecting coils in two halves symmetrically positioned about the neck of the tube and supplying to the coils in addition to the normal horizontal deflection sawtooth wave, a correction current which varies at frame frequency, such correction current being arranged to flow in opposite directions in the two halves of the coil. The beam deflection is therefore not affected by the correction current and is produced by the field resulting from the unequal currents in the two halves of the coil. The difference between the currents in the two coil halves however results in the production of a "quasi-quadripole" field the strength of which varies at frame frequency and this field produces the compensating "rotation" of the beam(s) which is required to correct the astigmatism. In one arrangement (Fig. 1), the two halves 13, 14 of theline deflection coil are supplied with the deflection sawtooth current via respective transformers 9, 10 from respective generators comprising transistors 5, 6 driven by switching pulses from the secondary windings 20, 21 of the output transformer 22 of the line drive stage and to produce the required correction current the operating potential is modulated at frame frequency by including in the connection between the junction of the two transistor generators (terminal 30) and the (centre) tap on potentiometers 32 connected across the operating voltage source +Vb, the secondary 33 of a transformer 34 the primary 37 of which is supplied from the frame sawtooth generator 35. The winding 33 is by-passed for line frequency by a capacitor 31 and the linearity of scan is controlled by known corrector means 15, 16. In a modification of this arrangement the two transformers 9, 10 are each replaced by a separate tapped winding as a common core and the frame frequency modulation is introduced via a transformer connected between the two transistors (Fig. 2 not shown). Fig. 3 shows a second arrangement in which the frame sawtooth from generator 35 is introduced via an emitter follows circuit 62 (Darling- ton configuration) which in effect reduces the impedance of the voltage source supplied to the transistors 5, 6 from potentiometer 32 (which must have a high resistance since it is connected across the supply voltage at terminal 2) so that the effect of asymmetry, due e.g., to the transistors 5, 6 not being identical, is reduced. To improve the symmetrical operation of the circuit a pair of complementary transistors 64 operates to control the magnitude of the switching voltage supplied to transistor 5 (via resistor 66) and to maintain the potential at terminal 30 (the point of symmetry) at the same value as that at the emitter output of the circuit 62. A resistor 66<SP>1</SP> of similar value to resistor 66 is included in the circuit of transistor 6. For the connection of EAST-WEST pincushion distortion the D.C. operating potential supplied at terminal 2 may be modulated by a parabolic function of frame frequency so that the line deflection sawtooth is also modulated but because of the symmetrical arrangement the correction current produced in the deflection coil halves 13, 14 is not modulated by this function. Centring of the beam is effected by a known circuit 67 and EHT a transformer 70 the primary of which is driven by the transistors 5, 6 supplies the D.C. operating potentials V 1 , V 2 for the complementary pair transistors 64 from a secondary winding 71 and provides the EHT voltage for the tube from a further secondary winding.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19681762843 DE1762843A1 (en) | 1968-09-07 | 1968-09-07 | Line deflection circuit |
DE19691928729 DE1928729A1 (en) | 1968-09-07 | 1969-06-06 | Line deflection circuitry in a color television receiver |
DE19691934568 DE1934568A1 (en) | 1969-07-08 | 1969-07-08 | Circuit arrangement for generating a line-frequency, saw-tooth-shaped current with an amplitude that changes at the raster frequency in an image display device |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1280877A true GB1280877A (en) | 1972-07-05 |
Family
ID=27181220
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB43840/69A Expired GB1280877A (en) | 1968-09-07 | 1969-09-04 | Line timebase circuit |
Country Status (7)
Country | Link |
---|---|
AT (1) | AT289220B (en) |
BE (1) | BE738578A (en) |
CH (1) | CH503427A (en) |
ES (1) | ES371284A1 (en) |
GB (1) | GB1280877A (en) |
NL (1) | NL6913394A (en) |
OA (1) | OA03644A (en) |
-
1969
- 1969-09-03 NL NL6913394A patent/NL6913394A/xx unknown
- 1969-09-04 CH CH1341669A patent/CH503427A/en not_active IP Right Cessation
- 1969-09-04 GB GB43840/69A patent/GB1280877A/en not_active Expired
- 1969-09-04 AT AT842269A patent/AT289220B/en not_active IP Right Cessation
- 1969-09-06 ES ES371284A patent/ES371284A1/en not_active Expired
- 1969-09-08 BE BE738578D patent/BE738578A/xx unknown
- 1969-11-05 OA OA53773A patent/OA03644A/en unknown
Also Published As
Publication number | Publication date |
---|---|
NL6913394A (en) | 1970-03-10 |
BE738578A (en) | 1970-03-09 |
AT289220B (en) | 1971-04-13 |
ES371284A1 (en) | 1971-09-01 |
OA03644A (en) | 1971-12-24 |
CH503427A (en) | 1971-02-15 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4063134A (en) | Raster distortion correction circuit | |
GB1190815A (en) | Improved Simplified Deflection System for a Plural Beam Cathode Ray Tube | |
US3968402A (en) | Raster distortion correcting circuit | |
GB1230162A (en) | ||
US3648099A (en) | Circuit arrangement in a display device for producing a line-frequency sawtooth current having an amplitude which varies at the frame frequency | |
US2007380A (en) | Cathode ray apparatus | |
US2654854A (en) | Image registration in color television systems or the like | |
US4227122A (en) | Convergence device for projection type color television system | |
US3504211A (en) | Electron beam control device for use with a cathode ray tube for dynamic correction of electron beam astigmatism and defocusing | |
US4024432A (en) | Circuit arrangement in an image display apparatus for (horizontal) line deflection | |
US3732458A (en) | Circuit arrangement for correcting the deflection of at least one electron beam in a television picture tube by means of a transductor | |
US3748531A (en) | Circuit arrangement for generating in a picture display device a sawtooth current of line frequency having an amplitude varying at field frequency | |
US2661443A (en) | Television keystone balance control circuit | |
GB1118641A (en) | Raster correction circuit | |
GB1280877A (en) | Line timebase circuit | |
US4234824A (en) | Combined linearity and side pincushion correction arrangement | |
US3422303A (en) | Convergence circuit for television receivers | |
GB1076953A (en) | Improvements in or relating to colour television receivers | |
KR100508191B1 (en) | Deflection Circuits and Vertical Deflection Circuits for Video Display Devices | |
US3441788A (en) | Circuit arrangements for dynamic lateral convergence | |
GB1237819A (en) | A circuit for producing magnetic vertical deflection in colour television apparatus | |
GB1393013A (en) | Television display apparatus employing convergence correction | |
EP0013598A1 (en) | Combined linearity and side pincushion correction arrangement | |
US4051512A (en) | Color television camera having at least two pick-up tubes | |
US3767962A (en) | Television convergence system |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PLNP | Patent lapsed through nonpayment of renewal fees |