Proximity alert system
US5298883A · kind A · utility
43Cited by
10References
11Claims
0Family size
Inventors
Key dates
| Filing date | Jan 17, 1992 |
| Grant date | Mar 29, 1994 |
| Priority date | — |
| Expiry date | Jan 17, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/38
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A proximity alert system including a pair of portable electronic, coded transmitter/receiver units designed to operate in a specific signal band. Each unit transmits a coded signal that is picked up by the other unit. The strength of the received coded signal controls the rate of an audible beeper. The rate of the beeper indicates the approximate distance between companion units. A direction-finder antenna is used to indicate the direction of the received coded signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.