Abstract text

The present invention relates to an optical holographic device and a corresponding method for reading out a data page recorded in a holographic recording medium (106) and carrying data modulated using a block modulation code, according to which a data page is divided into a number of blocks and a code constraint is applied defining the number of data symbols in a block having a predetermined symbol value. In order to avoid for storing any alignment marks for determining the alignment of the blocks of the block modulation code, a device is proposed having alignment means (115) for determining the alignment of the blocks in a detected imaged data page by iteratively determining, for a different alignment of the blocks in each iteration, whether for said alignments said code constraint is fulfilled or not, and decoding means (116) for decoding the block modulated data from said detected imaged data page based on the determined alignment of the blocks.