Resonator temperature compensated time base and watch using said time base
AssigneeAsulab S.A.
InventorsRudolf Dinger, Jean-Georges Michel, Claude-Eric Leuenberger
Life of this patent
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Abstract
To compensate for frequency variation in the quartz oscillator 4, 6 due to temperature variation, a second quartz oscillator 12, 14 forming a thermal sensor is employed. The beat frequency fB (circuit 16) which is counted in the counter 26 for a period of time T.sub.1 gives a measurement corresponding to temperature. The number which is thus counted is raised to its square and by means of the comparator 30 taken away from the pulses counted by the divider 8 with a periodicity T.sub.T. The system may be used to provide temperature compensation for a time keeping quartz time base.
Claims6
A time base provided with thermal compensation, comprising:
- a first frequency generator including a first oscillator provided with a piezoelectric resonator and producing a first signal at a first frequency which is dependent on temperature wherein said first resonator has a relationship between the relative variation in frequency (.DELTA.f/f) and the variation in temperature T with respect to its inversion temperature of the form (.DELTA.f/f)=.alpha..sub.O T+.beta..sub.O T.sup.2 +.gamma..sub.O T.sup.3 + . . . , wherein .alpha..sub.O, .beta..sub.O and .gamma..sub.O are constant coefficients;
- a second frequency generator including a second oscillator provided with a piezoelectric resonator and producing a second signal at a second frequency which is substantially linearly dependent on temperature in a range for which thermal compensation is desired, wherein said second resonator has a substantially linear relationship between the relative variation in frequency (.DELTA.f/f) and the variation in temperature T with respect to the inversion temperature of the first resonator, of the form:
- (.DELTA.f/f)=.alpha..sub.s T+.beta..sub.s T.sup.2, .alpha..sub.s and .beta..sub.s being coefficients such that .alpha..sub.s is at least one hundred times greater than .beta..sub.s, wherein .beta..sub.s is of the same order of magnitude as .beta..sub.o ;
- means for producing a signal which is representative of temperature, in response to the signals produced by said oscillators;
- means for producing a correction signal in response to said temperature signal, and
- means for adjusting the frequency of the signal produced by said first frequency generator in response to said correction signal.
Dependencies are inferred from the claim text.