| 摘要 |
PURPOSE:To reduce the necessary floor area of an oscillating circuit including an additional circuit on a printed-circuit board by packing a temperature compensating circuit and the oscillating circuit to different printed-circuit boards respectively in a double structure and setting a crystal oscillator into a space between both printed-circuit boards. CONSTITUTION:A circuit containing a thermistor and a capacitor connected in parallel is connected in series to a crystal oscillator 1. Furthermore an oscillating circuit 3 is added together with a temperature compensating circuit 2 which varies the apparent load capacity of the crystal oscillator by the variation of resistance value owing to the temperature change of the thermistor. The circuit 2 produces the capacity to offset the temperature-frequency characteristics of the oscillator 1. Then the circuits 2 and 3 are packed to different printed-circuit boards 4 and 5 respectively with a double structure formed by terminals 5, 6-. At the same time, the crystal oscillator 1 is set into a space between boards 4 and 5. In such a way, the necessary floor area can be reduced for the circuit 3 on a printed-circuit board. |
