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. 17, 1993
Filed:
Nov. 20, 1991
Ian Davidson, Lumphanan, GB;
Detector Electronics Corporation, Minneapolis, MN (US);
Abstract
An apparatus and method for sensing electro-magnetic radiation and analysing the resultant electrical signal waveform, in order to determine whether the radiation originates from a fire condition, monitors variations in the signal waveform over a predetermined period of time. The amplitudes of the successive transitions in the waveform and the elapsed time between the transitions are measured. Two two-dimensional matrices are produced. The first of these is made up of a plurality of co-ordinate points each corresponding to a respective pair of successively occurring signal transitions. The position of each such point in the matrix is dependent on the respective amplitudes of the two transitions making up each pair. The second matrix is also made up of a plurality of co-ordinate points each corresponding to a respective pair of the signal transitions. In the second matrix, however, the position of each point within the matrix depends on the amplitude excursion and the elapsed time between the two transitions of each pair. The matrices thus produced are compared with predetermined matrices corresponding, for example, to predetermined fire conditions or false alarm conditions, whereby to determine whether the sensed radiation has a pattern corresponding to a fire or a false alarm situation.