| 摘要 |
PURPOSE:To satisfy both functions, leading-in characteristics jitter suppression characteristics of a VFO circuit, by controlling the VFO circuit by generating a phase-synchronous VFO loop band switching circuit by a unit on a soft-sector system. CONSTITUTION:In a soft-sector system unit, a read signal from read head RH is inputted to controller 8 to set a high-gain state first. When clock bits in a phase- synchronous VFO lead-in area in a data format are continously counted by counter 9 as many as set, the VFO circuit is controlled to switch a VFO loop band, thereby obtaining a normal gain. Therefore, the switching of the VFO loop band is possible in high-density recording during and after the leading-in of an input signal, so that both functions of leading-in characteristics and jitter suppression characteristics the VFO circuit has can be satisfied. |
