| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve an error rate by preventing dead lock in a digital PLL circuit when a reproduced signal is deteriorated in quality. <P>SOLUTION: This recording medium playback apparatus has the digital PLL circuit comprising; a virtual VCO (voltage controlled oscillator) 35 of which the oscillation frequency varies according to control signals, a phase comparison part 34 which compares an input phase obtained by detecting the phase of an input signal by a phase detecting part 32 with the VCO phase from the above virtual VCO 35 to output a phase error; and an LPF 36 which is a loop filter for filtering the phase error from the phase comparison part 34 and sending the phase error to the virtual VCO 35 as a control signal, and a reset signal obtained by detecting deterioration in quality of a reproduced signal is inputted to a terminal 39. The oscillation frequency of the virtual VCO 35 is reset to an autonomous oscillation frequency by resetting the LPF 36 by the reset signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
