Patent ID: 8259873

Claim:
Method in a watermark decoder for correlating part of a received data signal containing a different watermarked data signal sections representing bits of a watermark information and each having a given length N, with a reference data signal section having said given length N, whereby at an encoder some of said watermark data signal sections were arranged at least two times in a successive manner in said data signal, said method comprising the steps: using a circular correlation, correlating said reference data signal section with a second part of a first received one of said successive watermark data signal sections and with a corresponding first part of the received repeated watermark data signal section following said first received one watermark data signal section, wherein said second part and said first part together form a section having said given length N; and depending on whether or not the resulting correlation value is greater than a pre-determined threshold value or smaller or equal than the negative value of said pre-determined threshold value, assigning to said correlation value either a first bit value of a watermark information or a second bit value different than said first bit value of said watermark information.