Magnetic disk device and linearity error correction method

A magnetic disk device comprising:

• a disk comprising a recording region including servo sectors;
• a head configured to write data to the disk and read data from the disk;
• and
• a controller configured to demodulate a plurality of pieces of demodulation data from servo data read from servo sectors, divide the demodulation data into a plurality of pieces of division data corresponding to division regions, perform linearity correction corresponding to a plurality of pieces of division data in each of the division regions,
• wherein the head comprises a first read head and a second read head, and
• the controller performs linearity correction which respectively correspond to the pieces of division data corresponding to first demodulation data obtained by demodulating first servo data read by the first read head and second demodulation data obtained by demodulating second servo data read by the second read head.

A magnetic disk device comprising:

• a disk comprising a recording region including servo sectors;
• a head configured to write data to the disk and read data from the disk;
• and
• a controller configured to demodulate a plurality of pieces of demodulation data from servo data read form servo sectors, divide the demodulation data into a plurality of pieces of division data correspond to division regions obtained by dividing a Lissajous waveform obtained from the N burst data and Q Burst data, perform linearity correction corresponding to the division regions obtained by dividing a Lissajous waveform, for every phase, divide the Lissajous waveform into a first division region from a first phase to a second phase, a second division region from the second phase to a third phase, a third division region from the third phase to a fourth phase, a fourth division region from the fourth phase to a fifth phase, a fifth division region from the fifth phase to a sixth phase, a sixth division region from the sixth phase to a seventh phase, a seventh division region from the seventh phase to an eighth phase, and an eighth division region from the eighth phase to a ninth phase, and correct a plurality of the linearity errors which respectively correspond to the first division region and the eight division region.

A linearity correction method applied to a magnetic disk device comprising a disk comprising a recording region including servo sectors, and a head configured to write data to the disk and read data from the disk, the method comprising:

• demodulating a plurality of pieces of demodulation data from servo data read form servo sectors, dividing the demodulation data into a plurality of pieces of division data correspond to division regions;
• performing linearity correction corresponding to a plurality of pieces of division data in each of the division regions;
• dividing the demodulation data into a plurality of pieces of division data based on the amplitude relationship and sign of the N Burst data and Q Burst data obtained from the demodulation data;
• and
• performing linearity correction based on a plurality of parameters which respectively correspond to the pieces of division data in each of the division regions.