US3718918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nuclear explosion detection systems
Assignee: United Kingdom Atomic Energy Authority
•
Filing: 1969-12-01
•
Granted: 1973-02-27
•
Expires: 1989-12-01
Abstract
Abstract This nuclear explosion detection system receives the radiated transient radiofrequency signal and the fast-rising and slowrising portions of the radiated transient optical signal, and indicates the occurrence of an explosion only if these signals satisfy selected criteria. The optical criteria include the relative durations of different parts of the optical signal and are checked by deriving time-intervals which include multiples of the durations of given parts of the optical signal, these derived time-intervals being compared with the durations of other parts. The time-intervals are derived by feeding clock pulses at suitable repetition frequencies to reversible counters in one direction during the given parts of the signal, and subsequently feeding clock pulses at appropriate submultiples of those repetition frequencies to the counters in the reverse direction to return them to predetermined conditions.
Inventors
- 👤 R Fothergill
- 👤 R Bennett
- 👤 G Risley
- 👤 W Weeks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:33
CPC Classifications
G; G21; G21J; G21J5/00; G04; G04F; G04F10/00; G04F10/04
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
234 words
A nuclear explosion detection system comprising means for receiving the transient radiofrequency signal radiated from the explosion, means for deriving from said radiofrequency signal a first output pulse if its rate of rise exceeds a predetermined value, its duration is less than a predetermined time and its field-strength exceeds a predetermined level, means for receiving the fast- and slow-rising portions of the transient optical signal radiated from the explosion and converting them to electrical signals, means for deriving from said fast-rising portion a second output pulse if its rate of rise exceeds a first predetermined value, means for deriving from said slow-rising portion a third output pulse if its rate of rise exceeds a predetermined value, and means for causing the occurrence of said first, second and third output pulses to indicate a nuclear explosion provided that: a. said second pulse occurs within a predetermined time of said first pulse, b. said second pulse does not exceed a predetermined duration unless the rate of rise exceeds a second rate of rise greater than said first rate of rise, c. said third pulse commences more than a predetermined time after the end of said second pulse but less than a time thereafter which exceeds the duration of said second pulse, d. said third pulse has a duration which exceeds the time between the end of the second pulse and the commencement of the third pulse.
Claim 2
Dependent Claim
234 words
A nuclear explosion detection system comprising means for receiving the transient radiofrequency signal radiated from the explosion, means for deriving from said radiofrequency signal a first output pulse if its rate of rise exceeds a predetermined value, its duration is less than a predetermined time and its field-strength exceeds a predetermined level, means for receiving the fast- and slow-rising portions of the transient optical signal radiated from the explosion and converting them to electrical signals, means for deriving from said fast-rising portion a second output pulse if its rate of rise exceeds a first predetermined value, means for deriving from said slow-rising portion a third output pulse if its rate of rise exceeds a predetermined value, and means for causing the occurrence of said first, second and third output pulses to indicate a nuclear explosion provided that: a. said second pulse occurs within a predetermined time of said first pulse, b. said second pulse does not exceed a predetermined duration unless the rate of rise exceeds a second rate of rise greater than said first rate of rise, c. said third pulse commences more than a predetermined time after the end of said second pulse but less than a time thereafter which exceeds the duration of said second pulse, d. said third pulse has a duration which exceeds the time between the end of the second pulse and the commencement of the third pulse.
Claim 3
Dependent Claim
35 words
A system as claimed in claim 1 wherein in proviso (c) said time thereafter which exceeds the duration of said second pulse is a function comprising a multiple of the duration of said second pulse.
Claim 4
Dependent Claim
14 words
A system as claimed in claim 2 wherein said function includes a fixed time.
Claim 5
Dependent Claim
48 words
A system as claimed in claim 1 wherein in proviso (d) said duration is either a time which is a function comprising a multiple of the time between the end of the second and the commencement of the third pulse or a predetermined time, whichever is the lesser.
Claim 6
Dependent Claim
35 words
A system as claimed in claim 1 wherein the first output pulse is only derived if said predetermined field strength level is reached within a predetermined time of the predetermined rate of rise and duration.
Claim 7
Dependent Claim
87 words
A nuclear explosion detection system including means for receiving the radiated transient optical signal, means for receiving the radiated transient radiofrequency signal, and means whereby the occurrence of an explosion cannot be indicated unless the radiofrequency signal and the optical frequency signal satisfies selected criteria , said system comprising means for deriving at least one time-interval which includes a multiple of the duration of a given part of the optical signal, and means for comparing the duration of another part of the optical signal with said time-interval.
Claim 8
Dependent Claim
87 words
A nuclear explosion detection system including means for receiving the radiated transient optical signal, means for receiving the radiated transient radiofrequency signal, and means whereby the occurrence of an explosion cannot be indicated unless the radiofrequency signal and the optical frequency signal satisfies selected criteria , said system comprising means for deriving at least one time-interval which includes a multiple of the duration of a given part of the optical signal, and means for comparing the duration of another part of the optical signal with said time-interval.
Claim 9
Dependent Claim
43 words
A system as claimed in claim 6 comprising means for receiving both the fast-rising and the slow-rising portioNs of the optical signal and means for indicating the occurrence of an explosion if said radiofrequency signal and both said optical portions satisfy selected criteria.
Claim 10
Dependent Claim
85 words
A system as claimed in claim 7 comprising time-interval deriving means arranged to derive a first time-interval which includes a multiple of the time to the first optical maximum, and a second time-interval which includes a multiple of the time to the first optical minimum, the comparing means being arranged to substantially compare the time to the first optical minimum with said first derived time-interval and to compare the time between the first optical minimum and the second optical maximum with said second derived time-interval.
Claim 11
Dependent Claim
16 words
A system as claimed in claim 8 wherein said first time-interval also includes a fixed time.
Claim 12
Independent Claim
28 words
A system as claimed in claims 8 wherein an explosion cannot be indicated unless substantially the time to the first optical minimum is less than said first time-interval.
Claim 13
Dependent Claim
39 words
A system as claimed in claim 10 wherein an explosion cannot be indicated unless the time between the first optical minimum and the second optical maximum exceeds said second derived time-interval or a fixed time, whichever is the lesser.
Claim 14
Dependent Claim
81 words
A system as claimed in claim 8 wherein the means for deriving a time-interval which is a multiple of the duration of a given part of the optical pulse comprises a reversible counter, means for feeding clock pulses at one repetition frequency to the counter during the given duration in one direction, and means for subsequently feeding clock pulses at a sub-multiple of said repetition frequency to the counter in the reverse direction to return the counter to a predetermined condition.
Claim 15
Dependent Claim
60 words
A system as claimed in claim 6 comprising means for deriving a time-interval which includes a multiple of the time to the first optical maximum, means for comparing said time-interval with substantially the time to the first optical minimum, and means whereby an explosion cannot be indicated unless the time to the first optical minimum is less than said time-interval.
Claim 16
Dependent Claim
15 words
A system as claimed in claim 13 wherein said time-interval also includes a fixed time.
Claim 17
Dependent Claim
59 words
A system as claimed in claim 6 comprising means for deriving a time-interval which includes a multiple of the time to the first optical maximum, means for comparing said time-interval with substantially the time to the first optical minimum, and means whereby an explosion cannot be indicated unless substantially the time to the first optical minimum exceeds said time-interval.
Claim 18
Dependent Claim
78 words
A system as claimed in claim 6 wherein the means for deriving a time-interval which is a multiple of the duration of a given part of the optical pulse comprises a reversible counter, means for feeding clock pulses at one repetition frequency during the given duration in one direction, and means for subsequently feeding clock pulses at a sub-multiple of said repetition frequency to the counter in the reverse direction to return the counter to a predetermined condition.
Claim 19
Dependent Claim
64 words
A system as claimed in claim 6 wherein the means for deriving a time-interval which is a multiple of the duration of a given part of the optical pulse comprises a capacitor arranged to be charged with a first time-constant during that part of the pulse and to be subsequently discharged with a second time-constant which is the given multiple of the first time-constant.
References Cited (Backward Citations)
US3147380A
Cited
US3138759A
Cited
US3281811A
Cited
US3467826A
Cited
US3421021A
Cited
US3524984A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |