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:
Dec. 13, 1994
Filed:
Feb. 04, 1993
Wayne C Fite, Elmhurst, IL (US);
William F Pranaitis, Jr, St. Charles, IL (US);
AT&T Corp., Murray Hill, NJ (US);
Abstract
A tone burst generator where a continuous tone voltage is applied across two series-connected semiconductor switches each having an ON state and an OFF state. A first control circuit controls the state of the first switch and the variable impedance in an intermediate region between its ON and OFF states to cause gradual, well-defined OFF/ON and ON/OFF transitions of the first switch. As a result of these first switch transitions, a voltage tone burst is generated that has precisely defined edges to eliminate clicking noise. The continuous tone voltage is of only one polarity--it has a non-zero DC component and an AC component having a peak-to-peak variation less the twice the magnitude of the non-zero DC component. A second control circuit controls the state of the second switch and the variable impedance in an intermediate region between its ON and OFF states to cause well defined ON/OFF and OFF/ON transitions of the second switch.