Method and apparatus for theft detection using digital signal processing
US5264829A · kind A · utility
6Cited by
3References
38Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 15, 1992 |
| Grant date | Nov 23, 1993 |
| Priority date | — |
| Expiry date | Jun 15, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2488
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
Signals received by an electronic article surveillance system are processed digitally to ascertain the variation in magnitude of successive signals and to prevent the actuation of an alarm when the variation exceeds a predetermined amount; and signals whose frequency components have been phase shifted from a filtering operation are restored by passing them into a signal delay circuit, tapping the delay circuit at several points therealong into associated signal channels selectively amplifying or attenuating the signal in each channel and combining the signals in each channel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.