GB749487A - Improvements in and relating to automatic vision gain control for television receivers and like apparatus - Google Patents
Improvements in and relating to automatic vision gain control for television receivers and like apparatusInfo
- Publication number
- GB749487A GB749487A GB3577453A GB3577453A GB749487A GB 749487 A GB749487 A GB 749487A GB 3577453 A GB3577453 A GB 3577453A GB 3577453 A GB3577453 A GB 3577453A GB 749487 A GB749487 A GB 749487A
- Authority
- GB
- United Kingdom
- Prior art keywords
- going
- valve
- negative
- resistor
- pulses
- 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
- H04N5/52—Automatic gain control
- H04N5/53—Keyed automatic gain control
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Feedback Control In General (AREA)
Abstract
749,487. Automatic gain control. WHITEIBBOTSON, Ltd. Oct. 5, 1954 [Dec. 23, 1953], No. 35774/53. Class 40 (5). In a receiver for positively-modulated television signals, positively-going synch. pulses are taken from a resistor R1 in the cathode circuit of a synch. separator V1 and are amplified in a valve V2. Negative-going synchpulse appear in the anode circuit of valve V2 and are differentiated by an R.C. network C2, R4. The resulting train of pulses comprises alternate negative- and positive-going " spikes " corresponding respectively to the leading and trailing edges of the synch, pulses. The tips of the negative-going " spikes " are restored to a fixed level by a D.C. restoring diode V4 and the pulse train applied to the grid of a valve V3. The valve V3 is so biased by a cathode resistor network R5, R10, R11 that conduction is caused by only the more positive part of the positive-going " spikes " in the pulse train. The resulting train of negative-going pulses in the anode circuit of the valve V3 is rectified by a diode V5 and smoothed by R.C. network R6, C4 to give a negative D.C. voltage which comprises the A.G.C. control voltage. A fixed positive bias may also be applied to the controlled valves by means of resistor R7. " Hunting " is prevented by shunting the A.G.C. line with a network comprising resistor R9, shunt rectifier V6 and condenser C6. The cathode bias resistor R5 may be variable and used as contrast control.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3577453A GB749487A (en) | 1953-12-23 | 1953-12-23 | Improvements in and relating to automatic vision gain control for television receivers and like apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3577453A GB749487A (en) | 1953-12-23 | 1953-12-23 | Improvements in and relating to automatic vision gain control for television receivers and like apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB749487A true GB749487A (en) | 1956-05-23 |
Family
ID=10381414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB3577453A Expired GB749487A (en) | 1953-12-23 | 1953-12-23 | Improvements in and relating to automatic vision gain control for television receivers and like apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB749487A (en) |
-
1953
- 1953-12-23 GB GB3577453A patent/GB749487A/en not_active Expired
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