Patent ID: 6278565
Filing Date: 2001-08-21
Classification: G11B

Abstract:
A circuit for reading out data from a disk having a plurality of tracks forming concentric circles partitioned into a plurality of sectors, each sector consisting of a first region recorded with servo data of the same frequency and a second region recorded with information data of different frequencies, said circuit comprising:pickup means (20) for picking up said data written on said disk and converting said data into an electrical signal;an amplifier which receives the electrical signal and outputs an amplified electrical signal;first filter means (23) for filtering signal frequencies corresponding only to the frequencies of said servo data in said picked-up electrical signal;second filter means (24) including a plurality of filters for filtering signal frequencies corresponding to each frequency of said information data in said picked-up electrical signal; andfilter selection control means (25) which receives said amplified electrical signal and determines, when said amplified electrical signal includes said information data, which of the different frequencies in which said information data included in said amplified electrical signal has been recorded, and for providing a servo signal to said first filter means to allow said first filter means (23) to be active when said picked-up electrical signal corresponds to said servo data and to allow a corresponding one of said filters in said second filter means (24) to be active according to which of the different frequencies is determined when said amplified electrical signal includes said information data.