发明名称 |
REPEATABLE RUNOUT (RRO) COMPENSATION METHODS AND APPARATUS FOR DATA STORAGE DEVICES |
摘要 |
<p>In one illustrative example, a method for use in reducing Repeatable Run Out (RRO) error in a data storage device involves obtaining an RRO measurement for each track of a limited number of N disk tracks; characterizing the RRO measurement for each track with real and imaginary values by performing a discrete Fourier transform (DFT) calculation on each RRO measurement; performing a least-squares fit on all of the real values to identify a first set of (n+1) coefficients of an nth-order polynomial function which is a function of disk track r and representable in the form A<SUB>i</SUB>(r)=a<SUB>n</SUB>r<SUP>n</SUP>+a<SUB>(n-1)</SUB>r<SUP>(n-1)</SUP>+ . . . +a<SUB>1</SUB>r+a<SUB>0</SUB>; and performing a least-squares fit on all of the imaginary values to identify a second set of (n+1) coefficients of an nth-order polynomial function which is a function of disk track r and representable in the form B<SUB>i</SUB>(r)=b<SUB>n</SUB>r<SUP>n</SUP>+b<SUB>(n-1)</SUB>r<SUP>(n-1)</SUP>+ . . . +b<SUB>1</SUB>r+b<SUB>0</SUB>. RRO compensation is performed based on the relation D<SUB>RRO</SUB>(r, s)=Sigma<SUB>i for all H </SUB>{A<SUB>i</SUB>(r)cos(i(s2pi/total_sectors))+B<SUB>i</SUB>(r)sin(i(s2pi/total_sectors))} where D<SUB>RRO </SUB>is the estimated RRO error; r is a track number; s is a sector number at track number r; i is an RRO harmonic number; H is a set of harmonics to be compensated; and total_sectors is a total number of sectors along track number r. Advantageously, RRO variations across the disk can be accurately compensated for with use of a small amount of memory.</p> |
申请公布号 |
SG135031(A1) |
申请公布日期 |
2007.09.28 |
申请号 |
SG20040025813 |
申请日期 |
2004.05.12 |
申请人 |
HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B. |
发明人 |
CHANG JEN-YUAN;RALEY JAY FRANCIS |
分类号 |
G11B21/10;G11B5/596;G11B20/10;(IPC1-7):G11B5/596 |
主分类号 |
G11B21/10 |
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