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:
Aug. 15, 1978
Filed:
May. 05, 1976
Donald P Massa, Hingham, MA (US);
Other;
Abstract
A mathematical analysis reveals the existence of circular motion in the head of a rotating phasor which represents the received signal in a Doppler intrusion alarm system in the presence of a moving target. The circular motion is virtually nonexistent when a moving target is absent regardless of the presence of environmental disturbances such as air turbulence and noise transients. The mathematical revelations are confirmed by a considerable amount of experimental data representing hundreds of thousands of measurements under various environmental conditions. The invention makes use of these new findings in combination with a new signal processing system which incorporates a circle detector for recognizing the presence of circular motion in the head of a rotating phasor when it occurs in the received signal, thus permitting absolute detection of a moving target even in the presence of environmental disturbances, such as air turbulence, while the system remains immune to false alarms due to these disturbances. The use of digital circuitry eliminates the need for sensitivity controls such as are required in prior art systems, thereby insuring correct installation of the inventive system with maximum reliability of operation.