US3924183A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency measurement by coincidence detection with standard frequency
Assignee: National Aeronautics and Space Administration
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Filing: 1974-09-13
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Granted: 1975-12-02
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Expires: 1994-09-13
Abstract
Abstract A method of measuring a desired frequency by comparing it with a standard frequency. The zero crossings of both frequencies are detected. A command pulse is generated at each coincidence and is used to start and stop a pair of frequency counters adapted to count the desired and standard frequencies. A measure of the desired frequency is obtained by multiplying the known standard frequency by the ratio between the desired count and the standard count obtained in the two frequency counters.
Inventors
- 👤 James C Administrator Fletcher
- 👤 Edward J Nossen
- 👤 Eugene R Starner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:15
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/02; G01R23/10
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
122 words
A method of measuring a desired frequency FDby comparing it to a standard frequency Fo, comprising: detecting each zero-crossing of the desired frequency and generating a narrow pulse at each such zero-crossing, detecting each zero-crossing of the standard frequency and generating a narrow pulse at each such zero-crossing, gating the train of narrow pulses obtained from the desired frequency with the train of narrow pulses obtained from the standard frequency, generating a coincidence pulse whenever said two trains of pulses are coincident, applying consecutive pairs of coincidence pulses to start and stop a pair of counters, one to counter providing a count Ndof the desired frequency and the other counter providing a count Noof the standard frequency, and obtaining FDfrom FD (Nd/No)Fo.
Claim 2
Independent Claim
122 words
A method of measuring a desired frequency FDby comparing it to a standard frequency Fo, comprising: detecting each zero-crossing of the desired frequency and generating a narrow pulse at each such zero-crossing, detecting each zero-crossing of the standard frequency and generating a narrow pulse at each such zero-crossing, gating the train of narrow pulses obtained from the desired frequency with the train of narrow pulses obtained from the standard frequency, generating a coincidence pulse whenever said two trains of pulses are coincident, applying consecutive pairs of coincidence pulses to start and stop a pair of counters, one to counter providing a count Ndof the desired frequency and the other counter providing a count Noof the standard frequency, and obtaining FDfrom FD (Nd/No)Fo.
Claim 3
Independent Claim
162 words
A system for measuring a desired frequency FDby comparing it to a standard frequency Fo, comprising: a first generator for detecting each zero-crossing of the desired frequency and generating a narrow pulse at each such zero-crossing, a second generator for detecting each zero-crossIng of the standard frequency and generating a narrow pulse at each such zero-crossing, a second generator for detecting each zero-crossing of the standard frequency and generating a narrow pulse at each such zero-crossing, an AND gate for gating the train of narrow pulses obtained from the desired frequency with the train of narrow pulses obtained from the standard frequency and generating a coincidence pulse whenever said two trains of pulses are coincident, a pair of counters adapted to receive consecutive pairs of coincidence pulses which start and stop said counters, one counter providing a count Ndof the desired frequency and the other counter providing a count Noof the standard frequency, and a computer for computing FDfrom FD (Nd/No) Fo.
Claim 4
Independent Claim
162 words
A system for measuring a desired frequency FDby comparing it to a standard frequency Fo, comprising: a first generator for detecting each zero-crossing of the desired frequency and generating a narrow pulse at each such zero-crossing, a second generator for detecting each zero-crossIng of the standard frequency and generating a narrow pulse at each such zero-crossing, a second generator for detecting each zero-crossing of the standard frequency and generating a narrow pulse at each such zero-crossing, an AND gate for gating the train of narrow pulses obtained from the desired frequency with the train of narrow pulses obtained from the standard frequency and generating a coincidence pulse whenever said two trains of pulses are coincident, a pair of counters adapted to receive consecutive pairs of coincidence pulses which start and stop said counters, one counter providing a count Ndof the desired frequency and the other counter providing a count Noof the standard frequency, and a computer for computing FDfrom FD (Nd/No) Fo.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |