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:
Jan. 12, 1999
Filed:
Sep. 20, 1996
Applicant:
Inventors:
Rong-Tyan Wu, Taichung, TW;
Herman Chung, Hsinchu, TW;
Assignee:
Holtek Microelectronics,Inc., Hsincho, TW;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ; H04M / ; H03M / ;
U.S. Cl.
CPC ...
379361 ; 379350 ; 379357 ; 379353 ; 341147 ;
Abstract
A cycle-modulating DTMF generator for generating a DTMF signal; the generator comprises a programmable time-pulse generator, counters or up/down counters, a memory unit for storing data, a digital adder, and a digital-to-analog converter. The circuit of such generator is substantially a digital circuit so as to overcome the problem of signal distortion, which usually exists in an analog circuit.