Coded acoustic alarm transmitter/receiver system
US4602357A · kind A · utility
48Cited by
17References
11Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 11, 1983 |
| Grant date | Jul 22, 1986 |
| Priority date | — |
| Expiry date | Apr 11, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B25/016
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The coded acoustic alarm transmitter/receiver system includes a transmitter for selectively providing both an audible alarm in the audio frequency range and a silent alarm in the ultrasonic frequency range. These alarm signals may be provided by a plurality of signals of different frequencies transmitted simultaneously in either the audio or ultrasonic frequency ranges. Receiver units are tuned to receive specific frequencies from a specific transmitter or group of transmitters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.