US3874296A
Expired / Lapsed
US
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Proximity fuse
Assignee: Kongsberg Gruppen ASA
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Filing: 1973-10-16
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Granted: 1975-04-01
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Expires: 1993-10-16
Abstract
Abstract A proximity fuse comprising a distance measuring system based on reflection of a frequency modulated signal having a linearly increasing sweep frequency. By selecting various modulation frequencies in the modulation oscillator the proximity fuse can be made to detonate at various given distances from the designated target. When the frequency modulated signal is phase modulated in step with a quasi-random code, the safety against unintentional detonation of the projectile due to undesired jamming signals or noise signals, is substantially increased.
Inventors
- 👤 Rolf Hedemark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:01
CPC Classifications
F; F42; F42C; F42C13/00; F42C13/04; F42C13/045; F42C13/042
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
38 words
Proximity fuse comprising a distance measuring system based on reflection of a frequency modulated signal having a linearly increasing sweep frequency, characterized in that the frequency modulated signal is phase modulated 180* in step with a quasirandom code.
Claim 2
Dependent Claim
38 words
Proximity fuse comprising a distance measuring system based on reflection of a frequency modulated signal having a linearly increasing sweep frequency, characterized in that the frequency modulated signal is phase modulated 180* in step with a quasirandom code.
Claim 3
Dependent Claim
31 words
Proximity fuse as indicated in claim 1, characterized in that the quasi-random code is generated in a coding unit comprising a clock generator driving a shift register via a feed-back circuit.
Claim 4
Dependent Claim
44 words
Proximity fuse as indicated in claim 2, characterized in that the quasi-random code is formed by a pulse train comprising logical bi-stable conditions which are periodically repeated in dependence on the storage capacity of the shift register and the design of the feed-back circuit.
Claim 5
Dependent Claim
53 words
Proximity fuse as indicated in claim 1, characterized in that the phase and frequency modulated signal is transmitted via and is reflected back to an antenna and the transmitted and the reflected signals are mixed in a mixer unit from which the differential signal is supplied to an amplifier with a narrow pass-band.
Claim 6
Dependent Claim
38 words
Proximity fuse as indicated in claim 4, characterized in that the transmitted and the reflected signals are in phase when the system is closer to the target than a given distance depending on the frequency of the generator.
Claim 7
Dependent Claim
36 words
Proximity fuse as indicated in claim 4, characterized in that a detector detects the differential signal if the latter appears in the pass-band of the amplifier and at the same time has a given threshold value.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |