The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 20, 2010
Filed:
Sep. 13, 2004
Peter Georg Baum, Hannover, DE;
Walter Voessing, Hannover, DE;
Peter Georg Baum, Hannover, DE;
Walter Voessing, Hannover, DE;
Thomson Licensing, Boulogne-Billancourt, FR;
Abstract
Spread spectrum technology is used for watermarking digital audio signals. To retrieve a watermark signal information bit from the spread spectrum at the receiver or decoder side, the received or replayed spectrum is convolved with a spreading function that is time-inverse with respect to the original spreading function. The pseudo noise sequences are modulated on carrier frequencies which are inserted at one or more frequency bands into the spectrum of an audio signal. The watermark signal decoder checks the frequency bands occupied by such carriers. The frequency band occupation information is signaled in advance, i.e. is transmitted already together with the frame data for the current frame, such that the watermark signal decoder knows before processing the following audio signal frame which carrier frequencies are occupied and must be used for the corresponding carrier demodulation, and which carrier frequencies need not be checked and demodulated.