| 摘要 |
PURPOSE:To reduce the fluctuation of a normal phase error due to the dispersion of parts or the change of an environment and to obtain the phase synchronous oscillator of high stability by providing an amplitude limit element in the input part of a loop filter. CONSTITUTION:Amplitude limit elements 21 and 22 such as a diode, etc., to limit the amplitude of an input voltage to a constant value are provided in the input part of a loop filter 2A. Accordingly, even when the amplitude of an output differential voltage in a phase comparator 1 is fluctuated, since the input differential voltage of the loop filter 2A is limited to the constant amplitude value, the fluctuation of the output differential voltage to accompany the characteristic change of the phase comparator 1 is absorbed and the phase- voltage converting gain of the phase comparator 1 can be suppressed to the constant value. Thus, the fluctuation of the normal phase error, which is caused by the dispersion of the parts and the change of the environment such as a temperature and a power source voltage, etc., can be made small and the phase synchronous oscillator of the high stability can be obtained. |
