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:
Sep. 16, 1980
Filed:
Apr. 21, 1978
Applicant:
Inventors:
Peter J Barowitz, Welwin, GB;
Roy Baxendale, Harpenden, GB;
Assignee:
Elliott Brothers (London) Limited, Chelmsford, GB;
Primary Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340566 ;
Abstract
Electric signals in two narrow frequency bands, centered on thirty-three and one hundred Hertz, arising from ground or airborne vibrations incident on one or more geophones are processed to give an alarm when signal components in the two bands exhibiting a rapid rise to greater than a predetermined amplitude level, characteristic of human footsteps within a protected area, occur at more than a predetermined repetition rate.