| 摘要 |
PURPOSE:To set a limit frequency accurately by inputting the limit frequency of an objective capture range or lock range to a comparator and adjusting the self-running frequency adjustment resistor of a voltage controlled oscillator so as to be synchronous with the limit frequency. CONSTITUTION:In the method setting the capture range or lock range of a phase locked loop circuit 1, a signal with the same frequency as a desired limit frequency of the capture range or lock range is supplied to an input terminal 6 of the phase locked loop circuit and a self-running frequency adjustment resistor 5 is changed while deciding the synchronizing state between the signal of the desired limit frequency and the output signal of the phase locked loop circuit 1 with the phase comparator. Then, the setting of the self-running frequency adjustment resistor 5 is substantially fixed at the start of synchronization of the output signal of the phase locked loop circuit 1 with respect to the signal of the desired limit frequency. Thus, the limit frequency of the lock range or the capture range is set accurately. |
