| 摘要 |
PURPOSE:To obtain an excellent reproduced signal even if bits have variance in depth by correcting the 1st and the 2nd reference signals by using sampled values which include pieces of information on bit depths of the tracking reference signals stored in sample value storage circuits previously, and performing tracking control on the basis of the corrected signals. CONSTITUTION:A switch SW2 is turned off prior to the play of a disk to allow a reproducing stylus to traverse recording tracks of the 1st and the 2nd tracking reference signals fp1 and fp2, and the sampled values of the reference signals are stored in the 1st and the 2nd sample value storage circuits SM1 and SM2; and the sample values of the reference signals fp1 and fp2 are compared by a comparator COMP with each other to generate a correcting signal of a signal level, which is supplied to a signal level correcting circuit SLC to perform level setting so that the two reference signals fp1 and fp2 are equal in signal level. Therefore, even if bits 2 and 3 forming the reference signals differ in depth, a control signal is generated after the levels of the reference signals are compensated, so the switch SW2 is turned on to put a control system in operation, thus performing the excellent tracking control. |
