| 摘要 |
PROBLEM TO BE SOLVED: To perform frequency switching at high speed, when outputting a frequency signal by using a plurality of PLL circuits and switching the output frequency from one PLL circuit to other PLL circuit.SOLUTION: A control unit 21 for outputting a control signal to PLL circuits 1, 2 and a switch 3 is provided with a memory 24 for storing frequency data associating the frequency f to be outputted and the timing t of the output frequency f. Before switching the switch 3, the output frequency f to be set in a PLL circuit 1 (2) at the switching destination is read previously, and set in the PLL circuit 1 (2) at the switching destination. Based on the timing t, the switch 3 is switched to the PLL circuit 1 (2) at the switching destination. |
