The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 11, 1980
Filed:
Nov. 01, 1978
Michael Slavin, Troy, MI (US);
Irvin B Rea, Royal Oak, MI (US);
Lectron Products, Inc., Troy, MI (US);
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.