Electronic wristwatch having dialing tone generator

Patent 4864604 Issued on September 5, 1989. Estimated Expiration Date:

April 21, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

DTMF Communication system
Patent #: 4087638
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Portable automatic number outpulser
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Method and circuit for telephone dialing signal generation
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Patent #: 4727570
Issued on: 02/23/1988
Inventor: Tarbouriech

Combined writing and signaling instrument Patent #: 4763355
Issued on: 08/09/1988
Inventor: Cox

Inventor

Aihara, Toshiharu

Assignee

Casio Computer Co., Ltd.

Application

No. 07/184293 filed on 04/21/1988

US Classes:

379/110.01, COMPOSITE SUBSTATION OR TERMINAL (E.G., HAVING CALCULATOR, RADIO)379/361, Electronic (e.g., tone generator)379/418, CALL SIGNAL GENERATING (E.G., RINGING OR TONE GENERATOR)968/968PRODUCING ACOUSTIC TIME SIGNALS [G04G 13/00]

Examiners

Primary: Schreyer, Stafford D.

Attorney, Agent or Firm

Frishauf, Holtz, Goodman & Woodward

International Classes

G04G 13/00 (20060101)
H04M 1/274 (20060101)
H04M 1/26 (20060101)
H04M 1/275 (20060101)
H04M 1/50 (20060101)

Foreign Application Priority Data

1986-04-07 JP

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.