Apparatus and method for the generation of directionally perceptible sound
US4926159A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 15, 1988 |
| Grant date | May 15, 1990 |
| Priority date | — |
| Expiry date | Jul 15, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B21/0415
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An apparatus and method to generate high intensity sound having a strong directional characteristic. The apparatus preferably uses a sound element (e.g. piezo sounder) which is capable of generating a high intensity, power efficient sound, but which has poor directional characteristics because of its high frequency (e.g. 3000 Hz). The apparatus drives the sound element with a variable frequency signal which sweeps across the resonant bandwidth of the sound element. The sweep rate of the frequency shift is less than about 1200 Hz which gives the sound a directional characteristic--resulting in periodic bursts of high intensity sound that is strongly directional. The apparatus may be incorporated into a wide variety of applications where high intensity, power efficient, strongly directional sound is desirable. In the preferred embodiment, the sound generator of the present invention is incorporated into a personal alert warning device worn by fireman or other safety personnel to emit a directional sound if the wearer becomes disabled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.