GB1244825A - Chrominance signal attenuation - Google Patents
Chrominance signal attenuationInfo
- Publication number
- GB1244825A GB1244825A GB4076/70A GB407670A GB1244825A GB 1244825 A GB1244825 A GB 1244825A GB 4076/70 A GB4076/70 A GB 4076/70A GB 407670 A GB407670 A GB 407670A GB 1244825 A GB1244825 A GB 1244825A
- Authority
- GB
- United Kingdom
- Prior art keywords
- chrominance signal
- amplitude
- signal
- colour
- attenuator
- 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
- 230000002238 attenuated effect Effects 0.000 abstract 2
- 230000000903 blocking effect Effects 0.000 abstract 2
- 230000000694 effects Effects 0.000 abstract 1
- 230000005669 field effect Effects 0.000 abstract 1
- 229920006395 saturated elastomer Polymers 0.000 abstract 1
- 238000001228 spectrum Methods 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/64—Circuits for processing colour signals
- H04N9/646—Circuits for processing colour signals for image enhancement, e.g. vertical detail restoration, cross-colour elimination, contour correction, chrominance trapping filters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/77—Circuits for processing the brightness signal and the chrominance signal relative to each other, e.g. adjusting the phase of the brightness signal relative to the colour signal, correcting differential gain or differential phase
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Processing Of Color Television Signals (AREA)
Abstract
1,244,825. Colour television. FERNSEH G.m.b.H. 28 Jan., 1970 [22 Feb., 1969], No. 4076/70. Heading H4F. To prevent a disturbing pattern being produced by the chrominance signal upon the reproduction of a colour television signal, the chrominance signal in the luminance channel is attenuated by an extent which is reduced with reducing amplitude of the chrominance signal. Preferably the chrominance signal is attenuated to a constant amplitude level e.g 20% of the maximum amplitude, so that in those parts of the picture having low colour saturation where the amplitude of the chrominance signal is less than this constant amplitude no attenuation is effected. Therefore in the weakly saturated parts of the picture the full frequency spectrum of the luminance signal is available and sudden changes of the luminance are faithfully reproduced without overshoot. In a first embodiment, Fig. 1, the colour television signal is fed via a delay device 2 (transit time equalizer) to a colour sub-carrier attenuator 3 whose blocking depth is controlled by a control voltage Us derived from the chrominance signal which is filtered out by band-pass filter 4, and passed via a threshold value device 5 which only passes that component which exceeds a predetermined amplitude to a rectifier 6. Attenuator 3 may comprise a conventional sub-carrier suppressor having a damped blocking circuit tuned to the sub-carrier frequency which is bridged by a controllable variable resistance e.g. in the form of a field effect transistor (Fig. 3, not shown). Devices 5 and 6 may be interchanged. In a second embodiment, Fig. 2, the colour television signal is applied directly and via a subcarrier attenuator 8 which is not controllable and effects a constant attenuation equal to that necessary for the maximum amplitude chrominance signal, to a blender mixer 9, and control voltage Us derived as in Fig. 1 being used to control the proportion of the two input signals appearing at the output. Devices 11 and 12 comprise transit time equalisers.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE1908897 | 1969-02-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1244825A true GB1244825A (en) | 1971-09-02 |
Family
ID=5725993
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB4076/70A Expired GB1244825A (en) | 1969-02-22 | 1970-01-28 | Chrominance signal attenuation |
Country Status (4)
| Country | Link |
|---|---|
| AT (1) | AT298582B (en) |
| DE (1) | DE1908897B1 (en) |
| GB (1) | GB1244825A (en) |
| NL (1) | NL7002446A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2203917A (en) * | 1987-03-27 | 1988-10-26 | Roger Neil Robinson | Improved encoder for television signals |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2280279A1 (en) * | 1974-07-26 | 1976-02-20 | Thomson Csf | DEVELOPMENT OF COLOR TELEVISION RECEIVERS OF THE SECAM SYSTEM |
| DE2515300C2 (en) * | 1975-04-08 | 1985-01-17 | Robert Bosch Gmbh, 7000 Stuttgart | Circuit arrangement for the reduction of color subcarrier-frequency signal components in a color video signal |
| US4167021A (en) * | 1977-12-12 | 1979-09-04 | Rca Corporation | Suppression of chrominance signal contamination of the luminance signal in a video signal processing system |
| US4206474A (en) * | 1978-08-30 | 1980-06-03 | Rca Corporation | Low-pass filter with remotely controllable rise time |
| DE3119653C2 (en) * | 1981-05-16 | 1985-05-09 | Grundig E.M.V. Elektro-Mechanische Versuchsanstalt Max Grundig holländ. Stiftung & Co KG, 8510 Fürth | Method for dynamic cross-color suppression, preferably in coders of color television signal sources |
| DE3343262A1 (en) * | 1983-11-30 | 1985-06-05 | Robert Bosch Gmbh, 7000 Stuttgart | METHOD AND ARRANGEMENT FOR SUPPRESSING INTERFERENCE IN THE LUMINOUS DENSITY CHANNEL OF A COLOR TELEVISION DECODER |
| DE3343261A1 (en) * | 1983-11-30 | 1985-06-05 | Robert Bosch Gmbh, 7000 Stuttgart | CIRCUIT TO REDUCE COLOR INTERPRETATION IN A COLOR TELEVISION CODE |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL220780A (en) * | 1956-09-19 |
-
1969
- 1969-02-22 DE DE19691908897D patent/DE1908897B1/en active Pending
-
1970
- 1970-01-28 GB GB4076/70A patent/GB1244825A/en not_active Expired
- 1970-02-09 AT AT116970A patent/AT298582B/en active
- 1970-02-20 NL NL7002446A patent/NL7002446A/xx unknown
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2203917A (en) * | 1987-03-27 | 1988-10-26 | Roger Neil Robinson | Improved encoder for television signals |
| US5047841A (en) * | 1987-03-27 | 1991-09-10 | Robinson Roger N | Encoder for television signals |
| GB2203917B (en) * | 1987-03-27 | 1991-10-30 | Roger Neil Robinson | Improved encoder for television signals |
Also Published As
| Publication number | Publication date |
|---|---|
| AT298582B (en) | 1972-05-10 |
| NL7002446A (en) | 1970-08-25 |
| DE1908897B1 (en) | 1970-07-02 |
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