SIGNAL PHASE SYNCHRONIZING APPARATUS AND SIGNAL PHASE SYNCHRONIZING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a signal phase synchronizing apparatus capable of stably extracting a clock with less frequency fluctuation from a PLL circuit by using a band pass filter employing a crystal oscillator.

SOLUTION: An XBPF 42 is an narrow band pass filter employing a crystal oscillator. When the XBPF 42 receives a reproduction signal, a stable reference frequency signal from which noise and jitter are eliminated is supplied to the PLL circuit 44. Since a VCO 33 of the PLL circuit 44 generates a clock phase-locked to the reference frequency signal, an ACD 46 samples the clock and converts an analog reproduction signal into a binary digital signal. Although a switch 49 is turned off and the reproduction signal to the XBPF 42 is lost when a timing control circuit 48 transmits a select signal on the way of a preamble part, the reference frequency signal is continuously supplied to the PLL circuit 44 by self-resonance of the crystal oscillator. Thus, the PLL circuit 44 can produce the clock without the need for carrying out phase locking.

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