Patent ID: 8726031

Claim:
A watermark generator for providing a watermark signal in dependence on binary message data, the watermark generator comprising: an information spreader configured to spread an information unit of the binary message data to a plurality of time-frequency-domain values, to acquire a spread information representation; a synchronization inserter configured to multiplicatively combine the spread information representation with a synchronization spread sequence to acquire a combined information-synchronization representation; and a watermark signal provider configured to provide the watermark signal on the basis of the combined information-synchronization representation; wherein the information spreader is configured to selectively spread a given bit onto a first bit representation, which is a positive multiple of a bit spread sequence, or onto a second bit representation, which is a negative multiple of the bit spread sequence, in dependence on the value of the given bit; wherein the information spreader is configured to acquire the spread information representation R according to R=c f ·m, wherein c f is a vector of size N f ×1 representing a bit spread sequence of frequency spreading width N f , wherein m is a vector of size 1×N mc representing N mc bits of the binary message data, wherein binary values of the bits are represented by entries of the vector m comprising a different sign; wherein the synchronization inserter is configured to combine the spread information with a synchronization sequence S according to C=S∘R, to acquire the combined information-synchronization representation C, wherein S designates a matrix of size N f ×N mc representing a sequence of N mc synchronization spread sequences; wherein ∘ designates a Schur element-wise product; and wherein the watermark generator comprises a hardware apparatus, a computer, or a combination of a hardware apparatus and a computer.