Patent US3868575A successfully refreshed from Google Patents.
US3868575A
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US
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Limited-range radiocommunication system with direction-indicating signaling means
Assignee: Thales SA
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Filing: 1973-05-24
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Granted: 1975-02-25
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Expires: 1993-05-24
Abstract
Abstract Vehicles traveling along a predetermined route are equipped with mobile receivers picking up traffic information from a radiating transmission line extending along the route, this information being modulated upon a first carrier F1 for vehicles traveling in one direction and upon a second carrier F2 for vehicles traveling in the opposite direction. Two ancillary short-range transmission stations, located at opposite ends of the line, radiate amplitude-modulated carrier waves directly to vehicles in the vicinity thereof whose receivers are tuned to either of the two carriers F1, F2. The first ancillary station emits the two carriers both modulated with a low-frequency signal f1 whereas the second ancillary station emits the same carriers modulated with a different low-frequency signal f2. A discriminating circuit aboard each vehicle, upon the reception of an amplitudemodulated carrier, tunes the receiver thereof either to the carrier F1 in response to a detected signal f1 or to the carrier F2 in response to a detected signal f2.
Inventors
- 👤 Jean Raymond Narbaits-Jaureguy
- 👤 Henri Billottet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:08
CPC Classifications
H; H04; H04B; H04B5/00; H04B5/20; H04B5/24; H04B5/26
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
289 words
In a limited-range radiocommunication system for the sending of messages from a fixed station provided with high-frequency information-transmitting means to a plurality of mobile stations provided with receiving means for high-frequency energy, said mobile stations traveling in either of two directions along a predetermined route with a first and a second point of entry at opposite ends of said route, the improvement wherein: said fixed station is provided with a radiating transmission line connected to said information-transmitting means, said line extending along said route; said information-transmitting means comprises a source of a first and a second carrier frequency, respectively allotted to travel in a first direction from said first to said second point and to travel in a second direction from said second to said first point, individually modulated with information relevant to the corresponding direction of travel; further comprisinga first ancillary short-range transmission station proximal to said first point for radiating both said first and said second carrier frequency, modulated with a first signal frequency, directly to nearby mobile stations entering upon said route in saId first direction; and a second ancillary short-range transmission station proximal to said second point for radiating both said first and said second carrier frequency, modulated with a second signal frequency, directly to nearby mobile stations entering upon said route in said second direction; each of said mobile stations including receiving means for picking up said carrier frequencies from said transmission line and from either of said ancillary transmission stations, detector means for said first and second signal frequencies connected to said receiving means, and message-reproducing means connected to said detector means, said receiving means being selectively tunable to either of said carrier frequencies in accordance with the output of said detector means.
Claim 2
Dependent Claim
289 words
In a limited-range radiocommunication system for the sending of messages from a fixed station provided with high-frequency information-transmitting means to a plurality of mobile stations provided with receiving means for high-frequency energy, said mobile stations traveling in either of two directions along a predetermined route with a first and a second point of entry at opposite ends of said route, the improvement wherein: said fixed station is provided with a radiating transmission line connected to said information-transmitting means, said line extending along said route; said information-transmitting means comprises a source of a first and a second carrier frequency, respectively allotted to travel in a first direction from said first to said second point and to travel in a second direction from said second to said first point, individually modulated with information relevant to the corresponding direction of travel; further comprisinga first ancillary short-range transmission station proximal to said first point for radiating both said first and said second carrier frequency, modulated with a first signal frequency, directly to nearby mobile stations entering upon said route in saId first direction; and a second ancillary short-range transmission station proximal to said second point for radiating both said first and said second carrier frequency, modulated with a second signal frequency, directly to nearby mobile stations entering upon said route in said second direction; each of said mobile stations including receiving means for picking up said carrier frequencies from said transmission line and from either of said ancillary transmission stations, detector means for said first and second signal frequencies connected to said receiving means, and message-reproducing means connected to said detector means, said receiving means being selectively tunable to either of said carrier frequencies in accordance with the output of said detector means.
Claim 3
Dependent Claim
37 words
The improvement defined in claim 1 wherein each of said ancillary transmission stations comprises a pair of transmitters for the two signal-modulated carrier frequencies, an antenna, and diplexer means connecting said pair of transmitters to said antenna.
Claim 4
Dependent Claim
60 words
The improvement defined in claim 1 wherein each of said mobile stations further includes discriminating means connected to said detector means and tuning means controlled by said discriminating means for automatically adjusting said receiving means to said first carrier frequency in response to said first signal frequency and to said second carrier frequency in response to said second signal frequency.
Claim 5
Dependent Claim
38 words
The improvement defined in claim 3 wherein said discriminating means comprises a pair of filters respectively tuned to said first and second signal frequencies, said tuning means including a switchover circuit connected to the outputs of said filters.
Claim 6
Dependent Claim
25 words
The improvement defined in claim 4 wherein said switchover circuit comprises a trigger circuit and a pair of relays alternately energizable by said trigger circuit.
Claim 7
Dependent Claim
39 words
The improvement defined in claim 5 wherein said trigger circuit is normally blocked, further comprising actuating means responsive to an output from said detector means for temporarily unblocking said trigger circuit to facilitate energization of either of said relays.
Claim 8
Dependent Claim
76 words
The improvement defined in claim 6 wherein each of said mobile stations is equipped with a separate receiver for radio broadcasts, said message-reproducing means comprising a loudspeaker common to said receiving means and said separate receiver, each of said mobile stations further comprising switch means normally connecting said loudspeaker to said separate receiver and control means for said switch means responsive to an output from said actuating means for connecting said loudspeaker to said detector means.
Claim 9
Dependent Claim
78 words
The improvement defined in claim 7 wherein said actuating means comprises a threshold circuit connected to said detector means for generating an unblocking signal for said trigger circuit in the presence of an incoming signal of predetermined minimum magnitude, said control means including logical circuitry connected to said threshold circuit and bistable means having two inputs connected to said logical circuitry for setting in the presence and resetting in the absence of said signal of predetermined minimum magnitude.
Claim 10
Dependent Claim
72 words
The improvement defined in claim 8 wherein said logical circuitry includes an OR gate with inputs connected to the outputs of said filters, an AND gate with inputs connected to the outputs of said OR gate and of said threshold circuit, said AND gate feeding one of the inputs of said bistable means, and inverter means inserted between the output of said threshold circuit and the other input of said bistable means.
Claim 11
Dependent Claim
33 words
The improvement defined in claim 9, further comprising a monostable circuit in the output of said threshold circuit delivering said unblocking signal to said trigger circuit, said AND gate and said inverter means.
Claim 12
Dependent Claim
18 words
The improvement defined in claim 9 wherein said tuning means comprises an intermediate-frequency stage of said receiving means.
Claim 13
Dependent Claim
78 words
The improvement defined in claim 11 wherein said carrier frequencies are frequency-modulated with said information and amplitude-modulated with said first and second signal frequencies, said detector means comprising amplitude-limiting means and a frequency demodulator connected in series to said intermediate-frequency stage and an amplitude detector connected to said intermediate-frequency stage in parallel with said amplitude-limiting means, said loudspeaker being connectable by said switch means to said frequency demodulator, said threshold circuit being connected to said second amplitude detector.
Claim 14
Dependent Claim
88 words
The improvement defined in claim 6 wherein said carrier frequencies are frequency-modulated with said information and amplitude-modulated with said first and second signal frequencies, said tuning means comprising an intermediate-frequency stage of said receiving means, said detector means comprising amplitude-limiting means and a frequency demodulator connected in series to said intermediate-frequency stage and an amplitude detector connected to said intermediate-frequency stage in parallel with said amplitude-limiting means, said message-reproducing means being connected to said frequency demodulator, said filters and said actuating means being connected to said amplitude detector.
Claim 15
Dependent Claim
20 words
The improvement defined in claim 13 wherein said actuating means comprises a threshold circuit and a monostable circuit in series.
Claim 16
Dependent Claim
27 words
The improvement defined in claim 1 wherein said mobile stations are carried aboard vehicles traveling said route, the messages sent from said fixed station pertaining to traffic.
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) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |