Apparatus and method for ideal value estimation in an optical PRML read channel

Apparatus for estimating values for Eight-Fourteen Modulated (EFM) data comprising:

• a peak detector receiving a first set of signals representing initial values of a sequence of EFM datums, each EFM datum having an initial value that is a member of a first set of values including {−b, −a, c, a, b} where |b|>|a|>|c|, the peak detector analyzing a first subsequence of the sequence of EFM datums to determine whether a peak has occurred and, if so, asserting a modify signal, the peak having a characteristic value that is a member of the first set of values;
• and
• modification circuitry receiving the modify signal, the modification circuitry responding to assertion of the modify signal by replacing the initial values of a second subsequence of the sequence EFM datums with revised values, the second subsequence of EFM datums following the first subsequence of EFM datums, each revised value of the second subsequence having an absolute value that is less than or equal to an absolute value of the characteristic value and is a member of the first set of values.