| 摘要 |
<p>A clock reproducing apparatus is adapted for reproducing a data existing point clock signal by using a reproduction signal obtained from a magnetic disc (1) on which clock patterns for clock reproduction are recorded in servo ares discretely provided independent of data recording area, which comprises: a voltage controlled oscillator (17) operative to oscillate the data existing point clock signal; a sampling circuit (11) for sampling the reproduction signal in synchronism with the data existing point clock signal; a phase information generator (14) for weighting-adding plural sample values before and after a reference sample value corresponding to the peak of a reproduced isolated waveform of the clock pattern to thereby generate phase information indicating a phase difference between the data existing point clock signal and a reproduction signal of the clock pattern; and a control voltage converter (15,16) for converting phase information generated by the phase information generator to a control voltage for controlling the voltage controlled oscillator (17). Moreover, the clock reproducing apparatus further comprises a phase synchronization loop control circuit (18) adapted to generate a phase comparison timing signal for allowing a sample value after a predetermined data existing point clock time from occurrence time of a signal which detects a unique pattern for recognizing an approximate existing time of the clock pattern. In addition, when there is employed a configuration to detect data in synchronism with the data existing point clock signal, a data recording apparatus is provided. <IMAGE></p> |
