US3789653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for measuring time differences between remote clocks and for synchronizing the same
Assignee: Office National d'Études et de Recherches Aérospatiales
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Filing: 1972-05-30
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Granted: 1974-02-05
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Expires: 1992-05-30
Abstract
Abstract System for measuring the time difference between a master clock and a slave clock located respectively in two remote stations and synchronizing these clocks. It comprises, in the master clock station, a time base generator controlled by the master clock, a source of light, an electro-optical detector, control means depending upon the time base generator for switching on the light source and control means depending upon the electro-optical detector for switching off the light source. The slave clock station comprises a time base generator controlled by the slave clock, an electro-optical detector detecting light from the master clock station, a chronometer switched on by the time base generator and switched off by the electro-optical detector and another chronometer switched on and off respectively by the first and second output signal of the electro-optical detector. Means are provided in the slave clock station for partially receiving and partially reflecting the light to the electro-optical detector at the master clock station causing the light source to produce a luminous signal whose start and end are split by a duration equal to twice the light propagation round trip time between the two stations.
Inventors
- 👤 H Brejaud
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:53
CPC Classifications
G; G04; G04F; G04F13/00; G04F13/02; G04C; G04C11/00; G04D; G04D7/00; G04D7/12; G04D7/1207
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
177 words
A system for measuring the time difference between a master clock and a slave clock located respectively in two remote stations and synchronizing said clocks comprising, in the master clock station, a first time base generator controlled by said master clock, a source of light, a first electro-optical detector, control means depending upon said first time base generator for switching on said light source, control means depending upon said first electro-optical detector for switching off said light source, and, in the slave clock station, a second time base generator controlled by said slave clock, a second electro-optical detector, a first chronometer switched on by said second time base generator and switched off by said second electro-optical detector, a second chronometer switched on and off respectively by the first and second output signal of said second electro-optical detector, means for reflecting to said master clock station the light received therefrom, whereby the light source produces a luminous signal whose start and end are split by a duration equal to twice the light propagation time between the two stations.
Claim 2
Independent Claim
177 words
A system for measuring the time difference between a master clock and a slave clock located respectively in two remote stations and synchronizing said clocks comprising, in the master clock station, a first time base generator controlled by said master clock, a source of light, a first electro-optical detector, control means depending upon said first time base generator for switching on said light source, control means depending upon said first electro-optical detector for switching off said light source, and, in the slave clock station, a second time base generator controlled by said slave clock, a second electro-optical detector, a first chronometer switched on by said second time base generator and switched off by said second electro-optical detector, a second chronometer switched on and off respectively by the first and second output signal of said second electro-optical detector, means for reflecting to said master clock station the light received therefrom, whereby the light source produces a luminous signal whose start and end are split by a duration equal to twice the light propagation time between the two stations.
Claim 3
Dependent Claim
76 words
A system for measuring the time difference between a master clock and a slave clock located respectively in two remote stations and synchronizing said clocks according to claim 1 in which the light source is a continuous laser and the switching-on and switching-off control means is a shutter means associated with said continuous laser, whereby the light source produces a luminous pulse whose duration is equal to twice the light propagation time between the two stations.
Claim 4
Dependent Claim
84 words
A system for measuring the time difference between a master clock and a slave clock located respectively in two remote stations and synchronizing said clocks according to claim 1 in which the light source is a CW laser and the switching-on and switching-off control means is a modulator associated with said pulse laser, whereby the light source produces a start luminous pulse and an end luminous pulse whose time separation is equal to twice the light propagation round trip time between the two stations.
Claim 5
Dependent Claim
80 words
A system for measuring the time difference between a master clock and a slave clock located respectively in two remote stations and synchronizing said clocks according to claim 1 in which the light source is an electroluminescent diode and the switching-on and switching-off means is a modulator associated with said electroluminescent diode, whereby the light source produces a start luminous and an end luminous pulse whose time separation is equal to twice the light propagation time between the two stations.
Claim 6
Dependent Claim
87 words
A system for measuring the time difference between a master clock and a slave clock located respectively in two remote stations and synchronizing said clocks according to claim 1 in which the light source is a Q-switched cavity resonator continuous laser and the switching-on and switching-off control means is a means for switching the Q of said cavity resonator, whereby the light source produces a start luminous and an end luminous pulse whose time separation is equal to twice the light propagation time between the two stations.
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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |