Patent ID: 8264933
Filing Date: 2012-09-11
Classification: G11B

Abstract:
1. A sync mark detector for detecting a sync mark having alternative polarities, comprising: an input terminal configured to receive a plurality of data bits, the plurality of data bits including a plurality of constant bit groups, each constant bit group comprising a plurality of consecutive bits of a same logic value; a first unit configured to output a plurality of constant bit length values that are representative of bit lengths of the plurality of constant bit groups, respectively; a second unit configured to output a plurality of combined bit length values, wherein each combined bit length value is representative of a sum of two consecutive constant bit length values; a third unit configured to compare each combined bit length value to a largest previous combined bit length value to determine a largest combined bit length value; a fourth unit configured to determine a threshold value based on the largest combined bit length value; and a fifth unit configured to output a sync mark detection signal when an individual combined bit length value is larger than the threshold value.