| 摘要 |
PURPOSE:To synchronize the frequency of an oscillator with a reference signal by amplifying the voltage variable of an output signal of an adder and keeping outputting the result till a difference component between an RF signal and the reference signal reaches a prescribed frequency or below. CONSTITUTION:When a band pass filter 6 and a detector A7 detect that a difference component between an RF signal and a reference signal is within a prescribed frequency band, the detector B8 retards the output of the detector A7 for a prescribed time, and a variable amplifier 9 is turned on. On the other hand, when a difference component between the filter 6 and the detector A is detected not to be within a prescribed frequency band, the amplifier 9 is immediately turned off. In this case, since the frequency of the oscillator is not synchronized with a reference signal, the difference component is again restores within a prescribed frequency band and the voltage variable of the output signal of the adder 3 is amplified and outputted to an adder 3 in a direction where the difference component is a prescribed frequency or below. The amplifier 9 amplifies the voltage variable of the output signal of the adder 3 and outputs it to the adder 3 and the difference component between the RF signal and the reference signal is pulled-in to the prescribed frequency or below to synchronize the frequency of the oscillator with the reference signal. |
