JPS54158150A - Crystal oscillation circuit - Google Patents

Abstract

PURPOSE: To realize both reduction of the position error and increment of the top temperature at one time by setting at least one of the crystal oscillators to the specified value in terms of the ralationship between the thickness, the width of the vibration arm and the space between the both vibration arms and with the conditions satisfied.

CONSTITUTION: The thickness and the width of the vibration arm are referred to as t and w each, with the space between the both arms referred to as S. For the relationship between S/t and top temperature To, To increases as S is increased, and the saturation is secured when S/t increases up to a certain level. Similarly, for the relationship between S/w and To, the larger S the higher To with the saturation secured when S/w increases up to a certain level. To keep To at 40°C or higher, t>50μ and S>100μ must be satisfied. Accordingly, both the position error< 4×10^-7 and the top temperature ≥40°C can be realized at one time by satisfying the following conditions: t>50μ and S>100μ and furthermore S/t≥ 1 and S/w≥0.25 respectively. As a result, the accuracy can be enhanced more for the electronic watch.

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