GB1557741A - Subscription television system - Google Patents
Subscription television systemInfo
- Publication number
- GB1557741A GB1557741A GB1776077A GB1776077A GB1557741A GB 1557741 A GB1557741 A GB 1557741A GB 1776077 A GB1776077 A GB 1776077A GB 1776077 A GB1776077 A GB 1776077A GB 1557741 A GB1557741 A GB 1557741A
- Authority
- GB
- United Kingdom
- Prior art keywords
- television system
- subscription television
- subscription
- television
- 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
- H04N7/00—Television systems
- H04N7/16—Analogue secrecy systems; Analogue subscription systems
- H04N7/167—Systems rendering the television signal unintelligible and subsequently intelligible
- H04N7/171—Systems operating in the amplitude domain of the television signal
- H04N7/1716—Systems operating in the amplitude domain of the television signal by inverting the polarity of active picture signal portions
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1776077A GB1557741A (en) | 1977-04-28 | 1977-04-28 | Subscription television system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1776077A GB1557741A (en) | 1977-04-28 | 1977-04-28 | Subscription television system |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1557741A true GB1557741A (en) | 1979-12-12 |
Family
ID=10100744
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1776077A Expired GB1557741A (en) | 1977-04-28 | 1977-04-28 | Subscription television system |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB1557741A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2482814A1 (en) * | 1980-05-14 | 1981-11-20 | Oak Industries Inc | METHOD AND DEVICE FOR ENCODING AND DECODING VIDEO SIGNALS BY REPETITIVE INVERSION OF THE POLARITY OF THESE SIGNALS |
GB2172463A (en) * | 1984-03-12 | 1986-09-17 | Dunn Instr Inc | Display for an image of normal or inverse polarity |
US4642688A (en) * | 1983-06-24 | 1987-02-10 | Scientific Atlanta, Inc. | Method and apparatus for creating encrypted and decrypted television signals |
-
1977
- 1977-04-28 GB GB1776077A patent/GB1557741A/en not_active Expired
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2482814A1 (en) * | 1980-05-14 | 1981-11-20 | Oak Industries Inc | METHOD AND DEVICE FOR ENCODING AND DECODING VIDEO SIGNALS BY REPETITIVE INVERSION OF THE POLARITY OF THESE SIGNALS |
US4642688A (en) * | 1983-06-24 | 1987-02-10 | Scientific Atlanta, Inc. | Method and apparatus for creating encrypted and decrypted television signals |
GB2172463A (en) * | 1984-03-12 | 1986-09-17 | Dunn Instr Inc | Display for an image of normal or inverse polarity |
GB2172463B (en) * | 1984-03-12 | 1989-07-19 | Dunn Instr Inc | Method and apparatus for controlling video display means for generating from a video signal normal or inverted images for photographing |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PE20 | Patent expired after termination of 20 years |
Effective date: 19970427 |