A method and apparatus are disclosed for detecting a synchronization mark in a received signal. The received signal is processed to compensate for a DC bias in the received signal, such as subtracting an average of a block of received samples from each sample in the block. A distance metric, such as a sum of square differences, is computed between the DC compensated received signal and an ideal version of the received signal expected when reading the synchronization mark. The synchronization mark is detected if the distance metric satisfies predefined criteria. The ideal version of the received signal can optionally be processed to compensate for a DC bias in the synchronization mark. A search for the synchronization mark search can be limited to time cycles that match a known phase.