Fire sensor cross-correlator circuit and method
US4639598A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 1985 |
| Grant date | Jan 27, 1987 |
| Priority date | — |
| Expiry date | May 17, 2005 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF23N2229/00
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A cross-correlation fire sensor circuit includes detectors responsive to heat and light radiation, respectively. Electrical signals from the detectors are processed in two distinct channels through low pass filters and samplers. The sampled signals from the two channels are multipled together and the products are summed over a selected interval to provide a correlation function. This function is compared with an adjustable threshold to provide an indication of fire sensing. The circuit is also included as an adjunct to an existing system to provide improved sensitivity for fire sensing in the presence of noise and enhanced discrimination against false alarms. A ratio window detector circuit is disclosed as an alternative cross-correlator for detected radiation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.