| 摘要 |
PROBLEM TO BE SOLVED: To surely lock a frequency at a desired reception frequency by comparing a receive frequency signal and a select frequency signal with each other, and locking the frequency of PLL transmission part, when the both are equal to each other and switching the frequency of the PLL transmissions part to the frequency of the receive frequency signal when they are different. SOLUTION: A normal reception detection part 5 detects normal receive data of a frequency F1. A receive data deciding means 21 decides that the frequency is F1 and outputs a receive F1/F2 signal of receive frequency F1 to an F1/F2 deciding means 22. A PLL frequency data output part 8, meanwhile, has already sent a frequency write signal of F2 out at this time through the operation of a timer 9 and also already has output a select F1/F2 signal of selected frequency F2 at the same time. Then the F1/F2 deciding means 22 outputs a frequency lock signal, after outputting a frequency switching signal whose frequency is F1 indicated by the receive F1/F2 signal, since the receive F1/F2 signal and select F1/F2 signal are different.
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