US3840812A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modulator arrangement for catv systems
Assignee: Hochiki Corp
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Filing: 1973-03-26
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Granted: 1974-10-08
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Expires: 1993-03-26
Abstract
Abstract A modulator capable of distinguishing up-signals from one another and used in a bi-directional CATV system intended for various kinds of information services includes an arrangement wherein output terminal of a modulating portion is connected to a down-signal input terminal via a filter circuit for letting an up-signal frequency band or predetermined frequencies transmitted from the modulating portion and within the up-signal frequency band pass therethrough. The input terminal of the modulating portion is connected to a down-signal output terminal via a filter circuit for letting signals having frequencies transmitted from suscriber''s alarm transmitters a filter circuit is connected between down-signal input and output terminals for letting downsignals pass therethrough.
Inventors
- 👤 T Takeuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:10
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/173; G; G08; G08B; G08B25/00; G08B25/01; G08B25/08; G08B25/085
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
189 words
An arrAngement in a CATV system comprising, in combination, a coaxial transmission line connecting said system to a plurality of subscribers; a transmitter at each subscriber and transmitting through said line an alarm signal identifying the respective subscriber, a supervisory station for receiving said alarm signal; a pair of terminals in said line and connected to a first and a second path therebetween, filter means in said first path and passing only down-signals therethrough, modulator means in said second path for generating a carrier wave of predetermined frequency outside the range of frequencies of said down-signals and modulating said carrier wave with said alarm signal transmitted from the respective subscriber transmitter to transmit thereby the modulated up-signal to said supervisory station through said line, and a pair of wave filters in said second path, said modulator means being between said wave filters, one of said wave filters being in proximity to the subscriber transmitter and passing only said alarm signal from the subscriber transmitter, the other one of said wave filters being in the proximity of said supervisory station and passing only the modulated up-signal from said modulator means.
Claim 2
Dependent Claim
189 words
An arrAngement in a CATV system comprising, in combination, a coaxial transmission line connecting said system to a plurality of subscribers; a transmitter at each subscriber and transmitting through said line an alarm signal identifying the respective subscriber, a supervisory station for receiving said alarm signal; a pair of terminals in said line and connected to a first and a second path therebetween, filter means in said first path and passing only down-signals therethrough, modulator means in said second path for generating a carrier wave of predetermined frequency outside the range of frequencies of said down-signals and modulating said carrier wave with said alarm signal transmitted from the respective subscriber transmitter to transmit thereby the modulated up-signal to said supervisory station through said line, and a pair of wave filters in said second path, said modulator means being between said wave filters, one of said wave filters being in proximity to the subscriber transmitter and passing only said alarm signal from the subscriber transmitter, the other one of said wave filters being in the proximity of said supervisory station and passing only the modulated up-signal from said modulator means.
Claim 3
Dependent Claim
41 words
The arrangement as defined in claim 1 wherein said filter means in said first path comprises a first filter in said one wave filter and a second filter in said other wave filter, said first and second filters being substantially identical.
Claim 4
Dependent Claim
27 words
The arrangement as defined in claim 2 including a third path between said terminals and having auxiliary filter means for passing up-signals therethrough from the other subscribers.
Claim 5
Dependent Claim
68 words
An arrangement in a CATV system as claimed in claim 1 including a pair of wave splitters (18) and (19) each comprising a filter circuit (22) allowing the whole of an up-signal frequency band (2) to pass therethrough, a filter circuit (23) through which bands except up-and down-signal frequency bands can pass, and filter circuits (24) permitting the whole of a down-signal frequency band (3) to pass therethrough.
Claim 6
Dependent Claim
124 words
An arrangement in a CATV system as claimed in claim 1 including a first wave splitter (18) which comprises a filter circuit (25) for letting only particular frequencies within the upsignal frequency band and transmitted from the modulating means (17) to pass therethrough, and a filter circuit (26) for letting up-signals pass therethrough, said up-signals having frequencies except those particular ones within the down-signal frequency band (3) and within the up-signal frequency band and transmitted from the modulating means (17) itself, and further including a second wave splitter (19) comprising a filter circuit (23) for letting bands except the up-and down-signal frequency bands pass therethrough, and a filter circuit which is the same as the filter circuit (26) of said first wave splitter (18).
Claim 7
Dependent Claim
46 words
An arrangement in a CATV system as claimed in claim 4 further comprising filter circuits (27) different from those of said pair of wave splitters (18) and (19), said latter filter circuits (27) letting pass up-signals having frequencies except those transmitted from said modulating means (17).
Claim 8
Dependent Claim
52 words
An arrangement in a CATV system as claimed in claim 1 including a pair of wave splitters (18, 19) each comprising a filter circuit (22) each allowing the whole of an up-signal frequency band (2) to pass therethrough, and filter circuits permitting the whole of a down-frequency band (3) to pass therethrough.
Claim 9
Dependent Claim
66 words
An arrangement in a CATV system as claimed in claim 1 comprising a wave splitter (19) which includes a filter circuit (25'') letting only particular frequencies within the upsignal frequency band and transmitted from said subscriber alarm transmitters, and filter circuits (28) for letting up-signals having frequencies except those transmitted from the modulation means (17) and the whole of the down frequency band to pass therethrough.
Claim 10
Dependent Claim
61 words
An arrangement in a CATV system as claimed in claim 1 including a wave splitter (19) which includes a filter circuit (25'') through which only particular frequencies transmitted from said subscriber alarm transmitters (14) and within the up-signal frequency band can pass, and a filtering circuit (29) for letting up signals having frequencies except those transmitted from said modulating means (17).
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |