| 摘要 |
PURPOSE:To improve the stability of a servo by adding a correction signal formed in response to the output of comparing means for comparing a phase error signal with the first and second reference signals corresponding to a phase standard value to the phase error signal. CONSTITUTION:A plurality of comparators 21, 22 are provided at the output side of a phase servo circuit 7. The level ranges of reference signals RF1, RF2 supplied to the comparators 21, 22 correspond to the range of a phase standard value to be used for a phase servo circuit 6. A correcting voltage composite circuit 25 generates a constant correction voltage when a signal from the circuit 7 is disposed between the levels of the signals RF1 and RF2, a correction voltage increasing in response to the degree when becoming lower than the level of the signal RF1, and a correction voltage decreasing in response to the degree when becoming the signal RF2 or higher. This correction voltage is added by an adder 28 to a phase servo signal. |
