US3740671A
Expired / Lapsed
US
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Filter for third-order phase-locked loops
Assignee: National Aeronautics and Space Administration
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Filing: 1972-04-06
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Granted: 1973-06-19
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Expires: 1992-04-06
Abstract
Abstract Filters for third-order phase-locked loops used in receivers to acquire and track carrier signals, particularly signals subject to high doppler-rate changes in frequency, are provided by employing a loop filter with an open-loop transfer function
Inventors
- 👤 R Crow
- 👤 R Tausworthe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:38
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085; H03L7/093; H03H; H03H11/00; H03H11/02; H03H11/04; H03H11/12; H03H11/1217
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
62 words
A filter for a third-order phase-locked loop in receiver systems, said filter having a transfer function substantially equal to F(s) (1 + Tau 2s/1 + Tau 1s) + 1/(1 + Tau 1s)( delta + Tau 3s) and, for a given set of loop constants, having a damping factor set equal to unity, said loop constants including desired bandwidth and steady-state phase error.
Claim 2
Dependent Claim
62 words
A filter for a third-order phase-locked loop in receiver systems, said filter having a transfer function substantially equal to F(s) (1 + Tau 2s/1 + Tau 1s) + 1/(1 + Tau 1s)( delta + Tau 3s) and, for a given set of loop constants, having a damping factor set equal to unity, said loop constants including desired bandwidth and steady-state phase error.
Claim 3
Dependent Claim
67 words
A filter as defined in claim 1 wherein said transfer function is expressed by the equivalent equation F''(s) ((1 + T2s)(1 + T4s)/(1 + T1s)(1 + T3s)) wherein T2T4/(T2 + T4)2 1/4 and T1 T3 such that said equivalent transfer function is equal to F''(s) (1 + T2s)2/(1 + T1s)2 whereby implementation is by two cascaded integrators, each having the transfer function (1 + T2s)/(1 + T1s).
Claim 4
Dependent Claim
68 words
In a third-order phase-locked loop for use in receivers to acquire and track carrier signals, a loop filter with an open-loop transfer function equal to F(s) (1 + Tau 2s/1 + Tau 1s) + 1/(1 + Tau 1s)( delta + Tau 3s) and, for a given set of loop constants, having a damping factor set equal to unity, said loop constants including desired bandwidth and steady-state phase error.
Claim 5
Dependent Claim
68 words
In a third-order phase-locked loop for use in receivers to acquire and track carrier signals, a loop filter with an open-loop transfer function equal to F(s) (1 + Tau 2s/1 + Tau 1s) + 1/(1 + Tau 1s)( delta + Tau 3s) and, for a given set of loop constants, having a damping factor set equal to unity, said loop constants including desired bandwidth and steady-state phase error.
Claim 6
Dependent Claim
68 words
A loop filter as defined in claim 3 wherein said transfer function is expressed by the equivalent equation F''(s) ((1 + T2s)(1 + T4s)/(1 + T1s)(1 + T3s)) wherein T2T4/(T2 + T4)2 1/4 and T1 T3 such that said equivalent transfer function is equal to F''(s) (1 + T2s)2/(1 + T1s)2 whereby implementation is by two cascade integrators, each having the transfer function (1 + T2s)/(1 + T1s).
References Cited (Backward Citations)
US3626301A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |