| 摘要 |
PROBLEM TO BE SOLVED: To enhance the reliability of a photodetection signal system by making the photodetection signal processing system a digital signal processing and changing over signal processing operations of the photodetection signal processing system in accordance with format of a medium to make the difference of signal processing performances due the variation of the disks smaller. SOLUTION: In a digital spindle servo filter, a servo gain switching control is performed so as to respectively perform corrections of +6dB/-6dB in an MD-DATA 1 format/an MD-DATA 2 format in accordance with the format of the medium and, then, a changeover control is executed so that band-pass characteristics of an ADPI band-pass filter respectively cope with 88.2 KHz/22.05 KHz. Next, a data reading control is executed by obtaining address information by reading out an ADPI signal. Thus, required parameter convertions of all photodetection signals are made possible by controls of a system controller or the like by subjecting them to digital processings after subjecting them to A/D conversions and a constant signal processing of them is performed. |
