Control circuit for a tone generator
US4193060A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1978 |
| Grant date | Mar 11, 1980 |
| Priority date | — |
| Expiry date | Nov 1, 1998 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60R2022/4866
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A control circuit for a tone generator that is adapted to cause the tone generator to produce a plurality of readily distinguishable audible sounds, including a chime sound, a pulse tone and a steady tone. The control circuit has particular application for use on an automobile to monitor such conditions as "seat belts buckled", "headlamps on", and "key in the ignition". The control circuit includes three oscillator circuits that are adapted to produce square wave output signals at three different frequencies. The chime sound is generated by pulse width modulating the highest frequency signal and "restriking" the decaying sound at the frequency of the lowest frequency oscillator. The steady tone is produced by driving the tone generator directly with the output signal from the highest frequency oscillator. To generate the pulse tone, the highest frequency oscillator is repeatedly enabled and disabled in accordance with the output signal from the middle frequency oscillator. Novel pulse width modulating circuitry for producing the chime sound is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.