Patent ID: 6556367
Filing Date: 2003-04-29
Classification: G11B

Abstract:
A storage apparatus comprising:a position sensitivity adjusting unit which detects the signal level at the intersection of position signals N and Q having different phases &phgr; by a predetermined track pitch (TP/n) which are demodulated from read signals of two-phase servo information buried and recorded in a disk medium, said position sensitivity adjusting unit making an adjustment of the gain of an AGC amplifier so that said intersection signal level coincides with a predetermined level; and a sensitivity correcting unit which corrects nonlinear position sensitivities relative to the actual track position X of two position signals N and Q output from said AGC amplifier, into linear position sensitivities, wherein said sensitivity correcting unit approximates two position signals N and Q relative to the actual track position X output from said AGC amplifier by cosine functions N=cos X Q=cos (Xâˆ’TP/n) said sensitivity correcting unit defining linear functions of two position signals Na and Qa which are corrected relative to the actual track position X, as Na=X Qa=Xâˆ’TP/n â€ƒto thereby obtain relational expressions of the two N=cos Na Q=cos Qa â€ƒsaid sensitivity correcting unit figuring out said corrected position signals Na and Qa from said relational expressions as Na=cosâˆ’1 N Qa=cosâˆ’1 Q â€ƒto thereby correct nonlinear position sensitivities into linear ones.