US4457003A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Time reference tracking loop for frequency hopping systems
Assignee: General Dynamics Mission Systems Inc
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Filing: 1982-06-21
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Granted: 1984-06-26
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Expires: 2002-06-21
Abstract
Abstract A system for using phase modulated information carried by a pilot tone generated in the transmitter of a frequency hopping communications system to synchronize the receivers dehop schedule generator with the transmitter's hop schedule generator.
Inventors
- 👤 Francis K. Reed
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:16
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/69; H04B1/713; H04B1/7156; H04B2001/71566
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
114 words
A method for dehopping a hopped frequency in a communications system comprising the steps of: supplying a pilot tone in a transmitter of the communications system which carries a frequency modulation that is correlated with an output of a hop schedule generator of said transmitter; recovering said pilot tone in a receiver of the Communications system; detecting a phase modulation of said recovered pilot tone; and correlating said phase modulation of said recovered pilot tone with an output of a dehop schedule generator to produce an error signal that is proportional to a system timing error; and applying said error signal to said dehop schedule generator to correct said system timing error toward zero.
Claim 2
Independent Claim
114 words
A method for dehopping a hopped frequency in a communications system comprising the steps of: supplying a pilot tone in a transmitter of the communications system which carries a frequency modulation that is correlated with an output of a hop schedule generator of said transmitter; recovering said pilot tone in a receiver of the Communications system; detecting a phase modulation of said recovered pilot tone; and correlating said phase modulation of said recovered pilot tone with an output of a dehop schedule generator to produce an error signal that is proportional to a system timing error; and applying said error signal to said dehop schedule generator to correct said system timing error toward zero.
Claim 3
Dependent Claim
149 words
A communications system having a transmitter for transmitting a frequency hopped signal and a receiver for receiving and frequency dehopping the signal comprising: means for generating a pilot tone modulated on a carrier of the transmitter, and carrier being frequency modulated by a signal having a correlation with an output of a hop schedule generator of the transmitter; means for sending said modulated carrier to the receiver; means for recovering said modulated pilot tone in the receiver; means for detecting a phase modulation from said recovered pilot tone; means for correlating said detected phase modulation with an output of a dehop schedule generator in the receiver to produce an error signal, said error signal being proportional to a timing error between said hop schedule generator and said dehop schedule generator; and means for applying said error signal to said dehop schedule generator for correcting said timing error toward zero.
Claim 4
Dependent Claim
149 words
A communications system having a transmitter for transmitting a frequency hopped signal and a receiver for receiving and frequency dehopping the signal comprising: means for generating a pilot tone modulated on a carrier of the transmitter, and carrier being frequency modulated by a signal having a correlation with an output of a hop schedule generator of the transmitter; means for sending said modulated carrier to the receiver; means for recovering said modulated pilot tone in the receiver; means for detecting a phase modulation from said recovered pilot tone; means for correlating said detected phase modulation with an output of a dehop schedule generator in the receiver to produce an error signal, said error signal being proportional to a timing error between said hop schedule generator and said dehop schedule generator; and means for applying said error signal to said dehop schedule generator for correcting said timing error toward zero.
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) | 1987-06-26 | 1987-12-26 | 1988-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-26 | 1991-12-26 | 1992-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-26 | 1995-12-26 | 1996-06-26 | $7700.00 | Window Closed / Lapsed |