Electronic siren
US4189718A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1978 |
| Grant date | Feb 19, 1980 |
| Priority date | — |
| Expiry date | Mar 2, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B3/10
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The invention is an electronic siren comprising in combination circuitry for generating one of a square wave siren and intelligible audio signal and a power output amplifier for audibly reproducing the signal. The amplifier includes transistor circuitry having base, emitter and collector means and a first circuit for coupling the signal-generating circuitry to the base means and one of said emitter and collector means for driving the transistors of the transistor circuitry into saturation in response to the siren signal. The first circuit includes circuitry for applying a dynamic biasing voltage derived from the siren signal to one of the emitter and collector means in phase with the voltage of the siren signal applied to the base means and of a plurality and opposition to the potential drop of the junction of the base means and the other of the emitter and collector means. Speaker circuitry is coupled to the other of the emitter and collector means for audibly reproducing the amplified selected one of the aforesaid signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.