| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an inexpensive reference frequency-generating apparatus whose temperature range is wide and which can output a high-accuracy reference frequency signal for a long time even after a reference signal cannot be acquired. <P>SOLUTION: A reference frequency generating apparatus 11 includes a GPS receiver 21, a PLL circuit 31, a detector 28, a storage 29 and a controller 22. The PLL circuit 31 controls a digital control oscillator 26 based on a synchronizing control signal obtained based on a reference signal from the GPS receiver 21. The storage 29 stores therein a corresponding relation between a control value of the synchronizing control signal and a voltage value/temperature at that time. If the reference signal cannot be obtained, the controller 22 determines a self-running control signal and controls the digital control oscillator 26 based on the corresponding relationship and a voltage and temperature detected by the detector 28. <P>COPYRIGHT: (C)2011,JPO&INPIT |
