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US3707709A Expired / Lapsed US ⏱️ 0.0 years remaining

Detection system

Assignee: Individual
•
Filing: 1970-09-24
•
Granted: 1972-12-26
•
Expires: 1990-09-24
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Abstract

Abstract A detection system designed primarily for detecting intruders of fenced-in areas such as yards, compounds, factory areas and the like. In the preferred embodiment, a chain-link metal fence extends about the area being monitored. A conductive cable extends parallel to the fence either on its inner or outer side. The cable is spaced uniformly from the fence which functions as an electrical ground. The cable is selected with a dimension and is spaced at a distance such as to establish uniform characteristic impedance between the cable and the grounded fence with the characteristic uniform impedance preferably in the order of 100 to 1,000 ohms. The cable is connected to a pulsing circuit and receiver so that the cable may be pulsed and reflections or partial reflections of the pulse signal received and displayed on an oscilloscope which is calibrated for a visual display and indication of the cable being monitored. Movement of people over or adjacent to the cable or the severing of the cable cause immediate mismatches which are reflected and suitably displayed on the oscilloscope at a location corresponding to the occurrence of the mismatch.

Inventors

  • 👤 David Wolf
  • 👤 Edward Blank

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-26 12:16
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; G08B13/26

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 109 words
A detection system for detecting movement of bodies over the perimeter of an area comprising, a transmission line consisting of an electrically conductive grounded fence at least in part encircling the area, and a cable means extending parallel to the fence and having a characteristic impedance defined by said fence and said cable, a pulsing circuit for generating electrical pulses, means coupling said pulsing circuit to said cable means whereby said pulses may be propogated along said cable means, receiving means for receiving pulse reflections from impedance mismatches along said cable means, and display means for visually displaying a representation of said cable means and impedance mismatches occuring thereon.
Claim 2
Dependent Claim 109 words
A detection system for detecting movement of bodies over the perimeter of an area comprising, a transmission line consisting of an electrically conductive grounded fence at least in part encircling the area, and a cable means extending parallel to the fence and having a characteristic impedance defined by said fence and said cable, a pulsing circuit for generating electrical pulses, means coupling said pulsing circuit to said cable means whereby said pulses may be propogated along said cable means, receiving means for receiving pulse reflections from impedance mismatches along said cable means, and display means for visually displaying a representation of said cable means and impedance mismatches occuring thereon.
Claim 3
Dependent Claim 67 words
A detection system as set forth in claim 1 wherein said display means includes a CRT display, means for displaying an electronic representation of said cable means on said CRT display in one configuration when the characteristic impedance of said cable means remains unchanged and said receiving means including means for displaying aberrations in said one configuration when the characteristic impedance of said cable means is changed.
Claim 4
Dependent Claim 40 words
A detection system as set forth in claim 2 wherein said cable means comprises a plurality of electrically conductive wires spaced apart, dielectric means supporting said wires in fixed, parallel arrangement, said wires supported in spaced relation to said fence.
Claim 5
Dependent Claim 28 words
A detection system as set forth in claim 2 having a plurality of dielectric means supporting said cable means parallel to said fence and spaced from the ground.
Claim 6
Dependent Claim 41 words
A detection system as set forth in claim 1 wherein said cable means includes end sections that extend angular to said fence to a point remote therefrom, said end sections having terminals adapted to be selectively connected to said pulsing circuit.

References Cited (Backward Citations)

US3031643A Cited
US3230518A Cited
US3560970A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-12-26 1976-06-26 1976-12-26 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-12-26 1980-06-26 1980-12-26 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-12-26 1984-06-26 1984-12-26 $7700.00 Window Closed / Lapsed

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