| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a temperature compensated oscillation circuit for effectively conducting temperature compensation while frequency is adjusted to the predetermined value. Ž<P>SOLUTION: The temperature compensated oscillation circuit includes a piezoelectric vibrator 14, an oscillation circuit 12 connected with a first voltage controlled variable capacitance circuit 16 and a second voltage controlled variable capacitance circuit 24 having temperature characteristic for canceling temperature characteristic of oscillation frequency of the piezoelectric vibrator 14, an AFC circuit 48 for adjusting the oscillation frequency to the predetermined value by outputting, to the first variable capacitance circuit 16, a voltage to control capacitance of the first variable capacitance circuit 16, and a temperature compensating circuit 40 for outputting a temperature compensating voltage having the primary temperature characteristic to the second variable capacitance circuit 24. The oscillation circuit 12 is further connected with a third voltage controlled variable capacitance circuit 32 that is connected to a temperature characteristic compensating circuit 54 for outputting a voltage having the primary temperature characteristic to the third variable capacitance circuit 32 by multiplying an output of a temperature sensor 38 with an output of the AFC circuit 48. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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