JPS5662487A - Automatic luminance adjusting circuit - Google Patents
Automatic luminance adjusting circuitInfo
- Publication number
- JPS5662487A JPS5662487A JP13966079A JP13966079A JPS5662487A JP S5662487 A JPS5662487 A JP S5662487A JP 13966079 A JP13966079 A JP 13966079A JP 13966079 A JP13966079 A JP 13966079A JP S5662487 A JPS5662487 A JP S5662487A
- Authority
- JP
- Japan
- Prior art keywords
- gain
- video amplifier
- circuit
- luminance
- level
- 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.)
- Granted
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)
- Picture Signal Circuits (AREA)
- Television Receiver Circuits (AREA)
Abstract
PURPOSE:To enable to emphasize the luminance of playback screen, when the input level to a video amplifier is small, by constituting that the level of drive signal can almost be at full range regradless of the input level of video amplifier, in an automatic luminance adjusting circuit for cathode-ray tubes. CONSTITUTION:The gain of a video amplifier circuit 25 is taken greater, and when an input video signal level is small, since the series circuit of diodes DR, DG, DB and a Zener diode DZ is nonconductive, the control output of a gain control circuit 29 is zero, and the gain of a video amplifier circuit 25 is greater. When either of cathode voltages KR, KG, KB of a cathode ray tube 10 is greater, either one of the said series circuit is conductive, and an output is obtained at a gain control circuit 29 to decrease the gain of the video amplifier circuit 25. Thus, since the gain of the video amplifier circuit is greater in comparison with conventional circuits, even if the input signal level is small, the luminance of playback screen can be emphasized, and when the input level is greater, the gain of the video amplifier circuit is lowered to avoid the luminance of playback screen unnecessarily made stronger.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13966079A JPS5662487A (en) | 1979-10-29 | 1979-10-29 | Automatic luminance adjusting circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13966079A JPS5662487A (en) | 1979-10-29 | 1979-10-29 | Automatic luminance adjusting circuit |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5662487A true JPS5662487A (en) | 1981-05-28 |
JPS6324356B2 JPS6324356B2 (en) | 1988-05-20 |
Family
ID=15250436
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP13966079A Granted JPS5662487A (en) | 1979-10-29 | 1979-10-29 | Automatic luminance adjusting circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5662487A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2640839A1 (en) * | 1988-12-20 | 1990-06-22 | Portenseigne Radiotechnique | VIDEO IMAGE REPRODUCTION DEVICE WITH CONTRAST ADJUSTMENT, AND METHOD OF ADJUSTING THE CONTRAST OF SUCH A REPRODUCTION DEVICE |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5126835A (en) * | 1974-08-28 | 1976-03-05 | Kojin Kk |
-
1979
- 1979-10-29 JP JP13966079A patent/JPS5662487A/en active Granted
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5126835A (en) * | 1974-08-28 | 1976-03-05 | Kojin Kk |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2640839A1 (en) * | 1988-12-20 | 1990-06-22 | Portenseigne Radiotechnique | VIDEO IMAGE REPRODUCTION DEVICE WITH CONTRAST ADJUSTMENT, AND METHOD OF ADJUSTING THE CONTRAST OF SUCH A REPRODUCTION DEVICE |
Also Published As
Publication number | Publication date |
---|---|
JPS6324356B2 (en) | 1988-05-20 |
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