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:
Sep. 05, 1989
Filed:
Apr. 21, 1988
Applicant:
Inventor:
Toshiharu Aihara, Oome, JP;
Assignee:
Casio Computer Co., Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04M / ; H04M / ;
U.S. Cl.
CPC ...
379110 ; 379361 ; 379418 ;
Abstract
A wristwatch equipped with a dialing tone generator employs a low-frequency oscillator as a reference signal oscillator. The reference signal is frequency-divided into first and second frequency-divided signals, the first frequency-divided signal being used to produce a low-frequency tone signal, the second frequency-divided signal being used to produce a high-frequency tone signal. Both these tone signals are rectangular waveforms which are filtered in corresponding low-pass filters, to output first and second sine-wave signals, which are then synthesized with each other to produce a desired dialing tone.