Position displacement detecting apparatus

摘要

An apparatus capable of detecting a displacement of a probe from a track of a recording medium caused by track fluctuations, vibrations at recording/reproducing period. For example, a probe 1 is maintained to vibrate at frequency f in the direction perpendicular to a data train 4 at an amplitude smaller than the width of the data train 4. In this case, the amplitude of a reproduced signal of the data train changes with the displacement between the probe 1 and the data train. The envelope signal i of the reproduced signal is phase detected using as a reference signal the vibration waveform (standard signal) at frequency fo of the probe 1, to obtain a signal proportional to the displacement from the data train. Using this signal, it becomes possible to feedback control the probe 1 so as to make it trace the data train.