GB1103664A - Improvements in or relating to television picture display apparatus - Google Patents
Improvements in or relating to television picture display apparatusInfo
- Publication number
- GB1103664A GB1103664A GB2384365A GB2384365A GB1103664A GB 1103664 A GB1103664 A GB 1103664A GB 2384365 A GB2384365 A GB 2384365A GB 2384365 A GB2384365 A GB 2384365A GB 1103664 A GB1103664 A GB 1103664A
- Authority
- GB
- United Kingdom
- Prior art keywords
- potential
- potential source
- tube
- potentiometer
- rectifier
- 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
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/57—Control of contrast or brightness
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Receiver Circuits (AREA)
Abstract
1,103,664. Television. COMMUNICATIONS PATENTS Ltd. 3 June, 1966 [4 June, 1965], No. 23843/65. Heading H4F. To counteract the change in amplitude of the video signal developed across load impedance R1 of video amplifying stage V1 when the contrast control, which is assumed to control the gain of a stage prior to valve V1, is adjusted, so varying the absolute potential of the black level of the video signal and the brightness of the picture displayed on cathode-ray tube 11, the control grid of tube 11 is arranged to have applied to it two potential sources connected in series. The first potential source having high internal impedance comprises a pulse generator 12 e.g. the line time base, pulses from which are applied through capacitor C1 to rectifier D 1 arranged to provide a direct current through potentiometer RV1. The second potential source comprises a rectifier D2 which provides in response to the video signals applied to the cathode of tube 11 a direct current through resistor R2 corresponding to the tops of the synchronizing pulses. Because the first potential source has a high internal impedance, variations in the second potential source are not readily swamped and the potential applied from the wiper of potentiometer RV1 to the grid of tube 11 varies in dependence upon the potential of the second potential source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2384365A GB1103664A (en) | 1965-06-04 | 1965-06-04 | Improvements in or relating to television picture display apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2384365A GB1103664A (en) | 1965-06-04 | 1965-06-04 | Improvements in or relating to television picture display apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1103664A true GB1103664A (en) | 1968-02-21 |
Family
ID=10202206
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2384365A Expired GB1103664A (en) | 1965-06-04 | 1965-06-04 | Improvements in or relating to television picture display apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1103664A (en) |
-
1965
- 1965-06-04 GB GB2384365A patent/GB1103664A/en not_active Expired
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