US4027264A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase lock loop multitone interference canceling system
Assignee: United States Department of the Army
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Filing: 1976-02-24
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Granted: 1977-05-31
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Expires: 1996-02-24
Abstract
Abstract An interference canceling system in which a phase lock loop is utilized as narrow band tracking filter to adaptively lock to interference tones to be canceled by a process of signal subtraction.
Inventors
- 👤 Frank S. Gutleber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:41
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/02; H03D3/24; H03D3/241; H03D3/248; H03L; H03L7/00; H03L7/06; H03L7/07; Y; Y10; Y10S; Y10S367/00; Y10S367/901
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
165 words
In a communication system for removing at least one undesired interfering continuous wave frequency from incoming wave energy including a wideband intelligence-bearing signal, an interference cancellation network for each said interfering frequency comprising: an ultra-narrow bandwidth phase lock loop continuously receptive of said input wave energy and capable of continuously tracking only said interfering continuous wave frequency, said phase lock loop including a voltage controlled oscillator which can be swept in frequency over the spectral range of the intelligence-bearing signal until the interfering frequency is encountered, said phase lock loop further including a phase detector coupled to said oscillator and to said incoming wave energy and a narrow band low pass filter. the output of said oscillator being a replica of said interfering continuous wave frequency, and circuit means responding to the output of said oscillator and to said incoming wave energy for canceling from said incoming wave energy said interfering continuous wave frequency only while said oscillator is frequency locked to the interfering frequency.
Claim 2
Dependent Claim
165 words
In a communication system for removing at least one undesired interfering continuous wave frequency from incoming wave energy including a wideband intelligence-bearing signal, an interference cancellation network for each said interfering frequency comprising: an ultra-narrow bandwidth phase lock loop continuously receptive of said input wave energy and capable of continuously tracking only said interfering continuous wave frequency, said phase lock loop including a voltage controlled oscillator which can be swept in frequency over the spectral range of the intelligence-bearing signal until the interfering frequency is encountered, said phase lock loop further including a phase detector coupled to said oscillator and to said incoming wave energy and a narrow band low pass filter. the output of said oscillator being a replica of said interfering continuous wave frequency, and circuit means responding to the output of said oscillator and to said incoming wave energy for canceling from said incoming wave energy said interfering continuous wave frequency only while said oscillator is frequency locked to the interfering frequency.
Claim 3
Dependent Claim
44 words
A system as recited in claim 1 wherein said incoming wave energy includes a plurality of interfering frequencies and comprising a like plurality of cascaded interference cancellation networks, each phase lock loop being set to lock on a different one of said interfering frequencies.
Claim 4
Dependent Claim
75 words
A system as set forth in claim 1 further including means for indicating that said phase lock loop has locked to said interfering frequency; and wherein said circuit means includes a 90 degree phase shifter and a variable amplifier responding to said 90 degree phase-shifted oscillator output, a subtractor coupled to said incoming wave energy, and means for coupling the output of said variable amplifier to said subtractor only while the lock condition is indicated.
Claim 5
Dependent Claim
54 words
A system as recited in claim 3 wherein said means for indicating includes phase detection means responsive to the 90 degree phase-shifted output of said oscillator and to said incoming wave energy and an integrator, said means for indicating providing a direct current voltages indicative of a lock to said interfering continuous wave frequency.
Claim 6
Dependent Claim
38 words
The system as recited in claim 4 including means for adjusting the gain of said amplifier to provide complete subtraction of said interfering continuous wave frequency from said incoming wave energy while said phase lock condition is indicated.
Claim 7
Dependent Claim
28 words
A system as recited in claim 5 wherein said means for adjusting includes a null detector connected in the output of said subtractor and coupled to said amplifier.
Claim 8
Dependent Claim
65 words
The system as recited in claim 4 wherein the output of said means for indicating is representative of the level of said interfering frequency, and including means for adjusting the gain of said amplifier in accordance with the output of said means for indicating to provide complete cancellation of said continuous wave frequency from said incoming wave energy while said phase lock condition is indicated.
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) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |