| 摘要 |
PURPOSE:To adjust highly accurately and prevent the destruction of data by the writing of an adjusting pattern by using a PLO signal including no jitter component as a reference signal when carrying out the phase adjustment of a reading clock of a magnetic disk. CONSTITUTION:A PLO signal is inputted to a terminal b of a receiver 1 and when carrying out the phase adjustment of a VCO 5 in a VFO 6, a terminal 1 d) of the receiver 1 to which the PLO signal is outputted by a multiplexer 2 is selected. The selected PLO signal is a standard when a self-advancing frequency is adjusted. A variable resistance 7 is adjusted observing an oscilloscope so as to have the normal value of a time difference DELTAt of a PLO signal Sp outputted from the multiplexer 2 in a phase comparator 3 and a signal Sv fed back from a VCO 5. Since the PLO signal Sp is formed based on a servo signal recorded on a magnetic disk, it is a kind of a read data, however, it is passes through a VFO circuit 12 similar to the VFO 6 once, so that a jitter component is not removed. |
