US3826863A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Subscription television system using audio and video carrier reversal
Assignee: OCI Communcations Inc
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Filing: 1973-02-09
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Granted: 1974-07-30
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Expires: 1993-02-09
Abstract
Abstract A subscription television system reverses the audio and video carriers within a particular channel on a random basis. A switching signal, nominally one Mhz beneath the video carrier, is transmitted to each of the receivers for use in effecting decoding at each receiver location.
Inventors
- 👤 A Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:22
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
134 words
In a subscription TV system having a central station, a plurality of receivers and a communication link therebetween, means at the central station for sending video and audio signals for a particular TV channel, means at the central station for periodically reversing the audio and video carriers in that channel at multiples of the video vertical sync signals, and means at the central station for sending a switching signal simultaneously with the reversal of the audio and video carriers, said switching signal being transmitted at a frequency within the band width of the particular channel, means at each receiver for receiving the audio and video signals, means at each receiver for receiving the switching signal, and means at each receiver for decoding the reversing audio and video signals in response to the switching signal.
Claim 2
Dependent Claim
134 words
In a subscription TV system having a central station, a plurality of receivers and a communication link therebetween, means at the central station for sending video and audio signals for a particular TV channel, means at the central station for periodically reversing the audio and video carriers in that channel at multiples of the video vertical sync signals, and means at the central station for sending a switching signal simultaneously with the reversal of the audio and video carriers, said switching signal being transmitted at a frequency within the band width of the particular channel, means at each receiver for receiving the audio and video signals, means at each receiver for receiving the switching signal, and means at each receiver for decoding the reversing audio and video signals in response to the switching signal.
Claim 3
Dependent Claim
21 words
The subscription TV system of claim 1 further characterized in that said switching signals are transmitted on a random time basis.
Claim 4
Dependent Claim
29 words
The subscription TV system of claim 1 further characterized in that the switching signal is transmitted at a frequency 1 Mhz away from that of the normal video carrier.
Claim 5
Dependent Claim
25 words
The subscription TV system of claim 3 further characterized in that the switching signal is at a frequency 1 Mhz below the normal video carrier.
Claim 6
Dependent Claim
43 words
The subscription TV system of claim 1 further characterized in that the means at each receiver for decoding the reversing audio and video signals includes a mixer and two oscillators connected thereto, said switching signal controlling which oscillator is connected to the mixer.
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) | 1977-07-29 | 1978-01-28 | 1978-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-29 | 1982-01-28 | 1982-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-29 | 1986-01-28 | 1986-07-30 | $7700.00 | Window Closed / Lapsed |