| 摘要 |
PURPOSE:To improve the inconvenience of the step temperature characteristics due to non-symmetry of the temperature characteristics of capacitors, by increasing the turn over point of the frequency versus temperature characteristics of the X-cut crystal oscillator of oscillation circuit than the Curie point of the temperature compensation capacitor. CONSTITUTION:The turn over point of the X-cut crystal oscillator in the crystal oscillation circuit of the electronic watch is increased by 1, 2, 3 deg.C than the Curie point of the temperature compensation capacitor. Thus, due to the non-symmetry of the capacitance versus temperature characteristics from the Curie point of the temperature compensation capacitor, in comparison with the step temperature characteristics 7 of conventional crystal oscillation circuits in which the turn over point of the crystal oscillator is taken the same as the Curie point of the capacitor, as shown in curves 8, 9, 10, the high temperature side changes toward advancing direction and the low temperature side changes toward delay direction to obtain more flat step versus temperature characteristics. |
