| 摘要 |
<p>An apparatus for recording and reproducing data signal carrying digital information at each reference phase (pi) appearing periodically includes detector (ZC, PD, 8, PCL) for detecting and producing a phase data at each sampling point. Two subsequently sampled phase data (Pi, Pi+1) are stored in latches (15, 14) for use in three comparators (17, 18, 19). The first comparator (18) compares the first sampled phase data (Pi+1) and the second sampled phase data (Pi). The second comparator (19) compares the first sampled phase data (Pi+1) with a predetermined value (N/2), and the third comparator (17) compares the second sampled phase data (Pi) with the predetermined value (N/2). Utilizing the outputs of the three comparators, a phase condition detector (20) detects whether or not a reference phase (pi) is contained between the two subsequent sampling points. A detection pulse generator (24, 26) is provided which generates a data detection pulse when the phase condition detector (20) detects the reference phase (pi).</p> |
