US Patent 7502187 Address mark detection

A recording system, such as a magnetic or optical recording system, employs an address mark (AM) detector that searches for an address mark pattern that is augmented by one or more bits of a preamble field so that a false detection rate is reduced. In one case, the address mark includes L bits, and the AM detector compares i) the input detected bits with ii) a SAM pattern of L bits augmented with m bits of the preamble to detect the SAM. In another case, the address mark includes less than L bits (e.g., L−k bits), and the AM detector compares i) the input detected bits with ii) a SAM bit-pattern of (L−k) bits augmented with m bits of the preamble to detect the SAM.