| 摘要 |
PURPOSE:To reduce the frequency fluctuation of an output signal compared with a normal state when the input signal of the phase locked loop circuit is instantaneously interrupted or the phase is changed. CONSTITUTION:The phase locked loop circuit provided with a voltage control oscillator 1 to output an output signal (b) which phase is locked to an input signal (a), frequency divider 2 to frequency divide the output signal (b), phase comparator 3 to detect phase difference between the output of the frequency divider 2 and the input signal (a) and low-pass filter 4 to smooth the output of the phase comparator 3 is equipped with diodes 5 and 6 for limiting the output voltage of the low-pass filter 4, resistors 7 and 10, capacitor 8 and buffer 9, the output voltage amplitude value of the low-pass filter 4 is limited, and the frequency fluctuation is reduced. |
