| 摘要 |
PURPOSE:To perform the temperature compensation of an oscillation frequency through simple constitution without using specially any external element by converting temperature variation into the variation in source voltage, and controlling an oscillator which varies in frequency according to the variation in source voltage. CONSTITUTION:The output of a temperature sensor 4 is converted by an A/D converter 5 into data, which is converted by a D/A converter 6 into the source voltage of a crystal oscillator 1. This voltage is lowest in a temperature region T2 including temperature T0 and the rises stepwise gradually and symmetrically at T2, T3, and T4 as the temperature rises or falls. The crystal oscillator 1 increases in oscillation frequency as the source voltage rises, and consequently, a decrease in oscillation frequency with temperature is canceled to perform the temperature compensation of the oscillation frequency. The output frequency of the oscillator 1 is divided by a frequency divider 2 to drive a timepiece display through a driving circuit 3. |
