EMBEDDING AND EXTRACTING SUPPLEMENTAL DATA IN AN INFORMATION SIGNAL

摘要

A method and an arrangement are disclosed for embedding supplemental data in an information signal such as a sigma-delta modulated audio signal. The encoded signal includes two or more channels, e.g. a left channel bit stream (z1) and a right channel bit stream (z2). The same supplemental data (w) is accommodated at corresponding predetermined bit positions, e.g. every M<th> bit position, of the bit streams. This allows detection and extraction of the supplemental data without the need for accommodating a sync pattern in the signal. At the receiving end, a sequence of M<th> bits from the first channel is compared with a corresponding sequence of M<th> bits from the second channel. If they are identical, the sequence is a candidate supplemental data sequence. This is done for different sequence positions (m) until the supplemental data has been found.