US4369462A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coding system for pay television
Assignee: Faurecia Clarion Electronics Co Ltd
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Filing: 1980-08-15
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Granted: 1983-01-18
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Expires: 2000-08-15
Abstract
Abstract A coding system for use in a television system wherein at least a part of a television signal is inverted by an encoder at a broadcasting station, according to a code signal and the coded television signal is decoded by decoders of specific subscribers to be reproduced on TV sets. The coding system is comprised of a clock oscillation means, a mode generating means for generating signals indicating plural inversion modes, a counter for counting clock signals from the clock oscillation means, a setting means for outputting a predetermined signal based on addresses provided corresponding to the respective inversion modes of the mode generating means and determined by an output from the counter, and a means for inserting the code signal during a vertical blanking period of the television signal. When the output signal of the mode generating means and the output signal of the setting means are in a given relation, the count value of the counter is used as the code signal.
Inventors
- 👤 Akimori Tomizawa
- 👤 Hiroshi Osaka
- 👤 Ryokichi Kanai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:16
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04N7/1675
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
209 words
A coding system producing an encode control signal for encoding a television signal by inverting at least a part of the television signal, which comprises: a first means for generating first random code signals; a second means for generating second random code signals corresponding to a predetermined value of said encode control signal; and a third means for inserting the first random code signals into the first five lines of the first six lines within a vertical blanking period of said television signal and the second random code signal into the sixth line to produce said encode control signal, said second means including: a clock-pulse generating means; a counter means for counting clock pulses from said clock-pulse generating means; an inversion mode generating means for producing inversion mode signals indicating a plurality of inversion modes; a program indicating means for producing program indicating signals; a setting means for providing predetermined signals in response to outputs from said counter means and said program indicating signal; a coincidence means for producing a coincidence signal when the mode signal and the predetermined signal are in a predetermined relation; and a means for producing the second random code signal corresponding to the count value of said counter in response to the coincidence signal.
Claim 2
Dependent Claim
209 words
A coding system producing an encode control signal for encoding a television signal by inverting at least a part of the television signal, which comprises: a first means for generating first random code signals; a second means for generating second random code signals corresponding to a predetermined value of said encode control signal; and a third means for inserting the first random code signals into the first five lines of the first six lines within a vertical blanking period of said television signal and the second random code signal into the sixth line to produce said encode control signal, said second means including: a clock-pulse generating means; a counter means for counting clock pulses from said clock-pulse generating means; an inversion mode generating means for producing inversion mode signals indicating a plurality of inversion modes; a program indicating means for producing program indicating signals; a setting means for providing predetermined signals in response to outputs from said counter means and said program indicating signal; a coincidence means for producing a coincidence signal when the mode signal and the predetermined signal are in a predetermined relation; and a means for producing the second random code signal corresponding to the count value of said counter in response to the coincidence signal.
Claim 3
Dependent Claim
35 words
A coding system as claimed in claim 1, wherein said mode generating means includes a random-pulse generating circuit and a timer, said timer being adapted to provide a clock pulse to said random-pulse generating circuit.
Claim 4
Dependent Claim
27 words
A coding system as claimed in claim 1, wherein said inversion mode generating means changes inversion mode signals when an average gradation of the television signal changes.
Claim 5
Dependent Claim
42 words
A coding system as claimed in claim 3, wherein said inversion mode generating means includes a detecting circuit for detecting an average gradation change of the television signal and a flip-flop circuit to which an output from said detecting circuit is applied.
Claim 6
Dependent Claim
22 words
A coding system as claimed in claim 4, wherein said detecting circuit includes a low-pass filter, a differentiating circuit and a comparator.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-17 | 1986-07-19 | 1987-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-17 | 1990-07-19 | 1991-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-17 | 1994-07-19 | 1995-01-18 | $7700.00 | Window Closed / Lapsed |