| 摘要 |
PURPOSE:To continue the controlled at frequency information just before the loss of a reception ratio frequency signal by storing the result of comparison of a phase comparator by a control circuit, and controlling the output frequency of a reference oscillator based on the result of comparison stored if the reception radio frequency signal is lost. CONSTITUTION:If the received radio frequency signal is lost, a switch 21 is opened and a switch 22 is closed. Furthermore, a control signal 13 is used to stop the counting of a counter 25. Thus, a DC analog voltage by a digital/analog converter 26 from the quantity stored in the counter 25 is outputted at an output terminal 23. That is, the information just before the received radio frequency signal is lost is stored in the counter 25 and the information is used at the loss of the received radio frequency signal to apply frequency control.
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