US3924059A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pay television systems
Assignee: INTRA-VIDEO Inc
•
Filing: 1973-12-28
•
Granted: 1975-12-02
•
Expires: 1993-12-28
Abstract
Abstract Reference pulses of opposite polarity to the horizontal sync pulses are added to the composite television signal just preceeding each horizontal sync pulse. The video portion of the signal is inverted for randomly selected fields. Coding bursts are added to the composite signal to indicate whether subsequent field is inverted. Transmitter clamped to reference pulse level. Reference pulse used for AGC in decoder. Video portion of received signal inverted in accordance with coding bursts. Audio program signals encoded by modulation on suppressed carrier centered above audio range. Barker signals transmitted on normal audio frequencies.
Inventors
- 👤 Irving Horowitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:05
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04N7/171; H04N7/1713
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
257 words
Apparatus for encoding a standard composite television signal having video signals for conveying the picture to be televised, said video signals having amplitudes varying between a first and second reference level respectively signifying picture black and white, said standard composite television signal further having horizontal and vertical synchronizing signals occurring during horizontal and vertical blanking intervals for synchronizing the television receiver to the television transmitter, said synchronizing signals having determined synchronizing levels and polarities relative to a determined one of said first and second reference levels, comprising, in combination, first transmitter circuit means having a signal input for receiving said composite television signal, an output, and a control input for receiving a control signal, for transmitting said composite television signal from said input to said output in such a manner that the polarity of said video signals relative to said selected one of said reference levels remains unchanged or is reversed throughout at least the subsequent field in dependence upon a control signal; controls means connected to said circuit means for furnishing a plurality of control signals, each during a randomly selected one of said vertical blanking intervals and applying said control signal to said control input of said first circuit means; and additional transmitter circuit means connected to said first transmitter circuit means and said control means for applying a coding signal to said composite television signal at a determined time instant in each of said randomly selected vertical blanking intervals in response to each of said control signals, thereby creating a coded composite television signal.
Claim 2
Dependent Claim
257 words
Apparatus for encoding a standard composite television signal having video signals for conveying the picture to be televised, said video signals having amplitudes varying between a first and second reference level respectively signifying picture black and white, said standard composite television signal further having horizontal and vertical synchronizing signals occurring during horizontal and vertical blanking intervals for synchronizing the television receiver to the television transmitter, said synchronizing signals having determined synchronizing levels and polarities relative to a determined one of said first and second reference levels, comprising, in combination, first transmitter circuit means having a signal input for receiving said composite television signal, an output, and a control input for receiving a control signal, for transmitting said composite television signal from said input to said output in such a manner that the polarity of said video signals relative to said selected one of said reference levels remains unchanged or is reversed throughout at least the subsequent field in dependence upon a control signal; controls means connected to said circuit means for furnishing a plurality of control signals, each during a randomly selected one of said vertical blanking intervals and applying said control signal to said control input of said first circuit means; and additional transmitter circuit means connected to said first transmitter circuit means and said control means for applying a coding signal to said composite television signal at a determined time instant in each of said randomly selected vertical blanking intervals in response to each of said control signals, thereby creating a coded composite television signal.
Claim 3
Dependent Claim
71 words
Apparatus as set forth in claim 1, wherein said first transmitter circuit means comprise means for transmitting said composite television signal from said input to said output in such a manner that the polarity of said video signals relative to said selected one of said reference levels remains unchanged in the absence of said control signal and is reversed throughout at least the subsequent field in response to said control signal.
Claim 4
Dependent Claim
163 words
Apparatus as set forth in claim 2, further comprising transmitting means for transmitting said coded composite television signal; receiving means for receiving said so-transmitted coded composite television signal and furnishing a received coded television signal in response thereto; first receiver circuit means connected to said receiving means for separating said coding signals from said received coded television signal thereby furnishing decoding signals; and second receiver circuit means connected to said first receiver circuit means and having an input for receiving said received coded television signal, an output, and a control input for receiving said decoding signals, for inverting the polarity of said video signals throughout the subsequent field relative to said determined one of said reference levels in response to a decoding signal and maintaining the polarity of said video signals relative to said selected one of said reference levels in the absence of said decoding signals, thereby furnishing a decoded composite television signal at said output of said second receiver circuit means.
Claim 5
Dependent Claim
55 words
Apparatus as set forth in claim 2, wherein said first transmitter circuit means comprise an inverting amplifier and a non-inverting amplifier connected in parallel and having a common input and a common output; and wherein said control means comprise enabling means for selectively enabling one and disabling the other of said inverting and non-inverting amplifiers.
Claim 6
Dependent Claim
68 words
Apparatus as set forth in claim 3, wherein said second receiver circuit means comprise an inverting and a non-inverting amplifier connected in parallel and having a common input and a common output, and receiver enabling means for selectively enabling one and disabling the other of said inverting and non-inverting amplifier means at least in part in dependence on the absence or presence of one of said decoding signals.
Claim 7
Dependent Claim
163 words
Apparatus as set forth in claim 5, wherein said encoded television signal further has reset bursts preceding each of said vertical blanking intervals; wherein said first receiver circuit means further comprises means for separating said reset bursts from said coded television signal thereby furnishing separated reset bursts; wherein said second receiver circuit means comprise a bistable circuit having a first and second stable state connected to said first receiver circuit means in such a manner that each of said decoding signals set said bistable circuit to said second stable state and that each of said separated reset bursts sets said bistable circuit to said first stable state, and connecting means for connecting said enabling means to said bistable circuit means in such a manner that said non-inverting amplifier is enabled when said bistable circuit is in said first stable state and said inverting amplifier is enabled only during said horizontal line trace intervals when said bistable circuit is in said first stable state.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |