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. 30, 1999
Filed:
Sep. 03, 1996
Applicant:
Inventor:
Rong-Tyan Wu, Taichung, TW;
Assignee:
Holtek Microelectronics Inc., Hsinchu, TW;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
379361 ; 379362 ; 379418 ; 364721 ;
Abstract
An adjustable-period dual-tone multifrequency (DTMF) generator, which includes a plurality of programmable counters or up/down counters, a control unit, a memory unit for storing data, a digital adder, and a digital-to-analog converter. The programmable counter and the control unit are combined together to form into at least two programmable counting address generators, in which the circuit is a digit-process circuit for overcoming the problem of signal distortion that usually exists in an analog circuit.