US3769579A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cable television monitoring system
Assignee: OCI Communcations Inc
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Filing: 1972-03-31
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Granted: 1973-10-30
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Expires: 1992-03-31
Abstract
Abstract A system for interrogating TV receivers connected to a common distribution system, for example a cable or the like, in which a start signal activates transponders at each of the TV receivers and a series of clock signals, transmitted during the vertical blanking interval of the TV signal, are used to determine the reply periods of the transponders.
Inventors
- 👤 R Harney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:56
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/173; H04N7/08; H04N7/087; H04N2007/17372
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
A method of interrogating a plurality of TV receivers connected to a common program distribution system, with each receiver having a transponder for signaling a common location, including the steps of: sending a start signal to a plurality of transponders over the distribution system, with the start signal providing no interruption to the TV programming and being unique in character, sending a series of clock signals during subsequent vertical blanking intervals of the TV signal, groups of transponders replying to the start signal between subsequent vertical blanking intervals as determined by the number of clock signals received by the individual transponders.
Claim 2
Independent Claim
101 words
A method of interrogating a plurality of TV receivers connected to a common program distribution system, with each receiver having a transponder for signaling a common location, including the steps of: sending a start signal to a plurality of transponders over the distribution system, with the start signal providing no interruption to the TV programming and being unique in character, sending a series of clock signals during subsequent vertical blanking intervals of the TV signal, groups of transponders replying to the start signal between subsequent vertical blanking intervals as determined by the number of clock signals received by the individual transponders.
Claim 3
Dependent Claim
23 words
The method of claim 1 further characterized in that the start signal is sent during the vertical blanking interval of the TV signal.
Claim 4
Dependent Claim
37 words
The method of claim 1 further characterized by the step of generating independent clock signals at each of the transponders, said clock signals being generated in response to received vertical sync signals during the vertical blanking intervals.
Claim 5
Dependent Claim
23 words
The method of claim 1 further characterized by and including the step of coding the transponder reply to provide different types of information.
Claim 6
Dependent Claim
40 words
The method of claim 1 further characterized in that all of said transponders receive the initial start signal, with said transponders replying in predetermined groups, with all the transponders in each group replying after a given number of clock signals.
Claim 7
Dependent Claim
30 words
The method of claim 1 further characterized by the step of cancelling an interrogation at a transponder if the TV channel is changed after the interrogation and prior to reply.
Claim 8
Dependent Claim
28 words
The method of claim 1 further characterized by the step of preventing a reply from an interrogated transponder if the TV signal is not at a predetermined level.
Claim 9
Dependent Claim
31 words
The method of claim 1 further characterizeD by the step of preventing a reply from an interrogated transponder if there is an absence of vertical sync pulses in the TV signal.
Claim 10
Dependent Claim
24 words
The method of claim 1 further characterized in that the start signal consists of an absence of horizontal sync pulses for a predetermined period.
Claim 11
Dependent Claim
19 words
The method of claim 9 further characterized in that the start signal takes place during the vertical blanking interval.
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) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |