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:
Apr. 14, 1987
Filed:
Jul. 22, 1981
Dennis J Denen, Columbus, OH (US);
Floyd Bell Associates, Inc., Columbus, OH (US);
Abstract
A telephone ringer circuit having a ring signal detection network serving to detect ring signals utilizing an R-C network and operating in conjunction with a threshold responsive detection device. Upon the detection of a valid ring signal, the resistance component of the R-C network is by-passed to permit low impedance passage of electrical energy into the ringing components of the circuit. Drive for a piezoelectric crystal driven audio output is provided by two push-pull amplification stages, configured as integrators, so as to effect crystal drive with trapezoidal shaped waveforms wherein high harmonics are not evolved. Improved loudness and sound quality are achieved with the circuit.