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Electronic timepiece with temperature compensation

  • US 4,453,834 A
  • Filed: 07/01/1982
  • Issued: 06/12/1984
  • Est. Priority Date: 07/03/1981
  • Status: Expired due to Term
First Claim
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1. An electronic timepiece powered by a battery, having unit time signal generating circuit means for generating a unit time signal, said unit time signal generating circuit means comprising a quartz crystal oscillator circuit for producing a timebase signal, said quartz crystal oscillator circuit displaying a quadratic relationship between ambient operating temperature and frequency of oscillation, and frequency divider circuit means coupled to receive said timebase signal for performing frequency division thereof to thereby generate a plurality of timing signals of different frequencies including said unit time signal, said electronic timepiece further comprising display drive circuit means coupled to receive said unit time signal, a display device driven by said display drive circuit means to display time information in accordance with said unit time signal, and temperature compensation means for compensating changes in the period of said unit time signal resulting from the effects of changes in the ambient operating temperature upon the oscillation frequency of said quartz crystal oscillator circuit, said temperature compensation circuit means comprising:

  • temperature measuring circuit means for sensing the ambient temperature of said quartz crystal oscillator circuit to produce temperature information indicative thereof, as a digital value, and;

    frequency compensation means for producing the square of said digital value representing temperature information from said temperature measurement circuit means and for applying a value resulting from said squaring operation to control the operation of said unit time signal generating circuit means such as to compensate the period thereof for the effects of ambient temperature variations;

    said temperature measurement circuit means including temperature sensing circuit means for producing a temperature sensing signal whose repetition frequency varies in accordance with ambient temperature, slope adjustment circuit means for dividing the frequency of said temperature sensing signal by a factor which is determined in accordance with a preset value, numeric conversion means for converting an output signal produced by said slope adjustment circuit means to temperature information in digital form, and offset adjustment circuit means for effecting offset compensation of said digital temperature information from said numeric conversion circuit means.

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