The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 10, 1977
Filed:
Dec. 23, 1975
G Kirby Miller, Saratoga, CA (US);
GTE Sylvania Incorporated, Mountain View, CA (US);
Abstract
An active ultrasonic perimeter intrusion detection system comprises an elongated flexible electret tape capable of being stored on and deployed from a reel or the like and connectable when deployed to a signal generator operating at ultrasonic frequencies and to a receiver having a signal processing and alarm capability. The tape comprises an electret layer sandwiched between relatively fixed and movable conductive strips and lies flat on a surface adjacent to the area to be protected such as the walls or ceiling of a room or the perimeter of a ground area. The movable stip produces a substantially undirectional ultrasonic beam outwardly from the tape and along its length so as to illuminate objects that cross over the tape. This causes a reflection of the ultrasonic signal and doppler shifting of its frequency which is detected by the tape, the output of which passes to the receiver for indicating the intrusion. One tape preferably functions as the transmitting and receiving transducer, although separate juxtaposed tapes may also be used for these purposes.