APPARATUS FOR INSPECTING DISC SHAPED RECORDING MEDIUM

摘要

PURPOSE:To perform the inspection processing of the presence of the abnormality of a track by writing the level of a DC signal in the partial section of the track while said level is attenuated in a predetermined time constant after erasion was performed by the DC signal and repeatedly performing the erasion of recorded content. CONSTITUTION:When a disc 11 is once rotated and the erasion of all sections of a track is performed, a time control part 1 does not output a DC current control signal '1' and a DC current attenuated in a predetermined time constant begins to discharge from a condenser 14 and is applied to a head 3 as a writing current through a writing control gate circuit 8 and a separation part 9 to perform the writing of the track succeedingly. When the discharge current of the condenser 14 comes to 0, the control part 2 outputs no writing control signal '1' and the circuit 8 is closed and the writing operation of this track is entirely finished. By this method, the presence of an extra error can be accurately performed over all sections of the tracks of a hard magnetic disc without receiving the effect of the transitional response of the head.