Coding process for inserting an inaudible data signal into an audio signal, decoding process, coder and decoder

US6584138B1 · kind B1 · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Christian Neubauer · Nuremberg, DE
• Ernst Eberlein · Erlangen, DE
• Roland Plankenbühler · Wendelstein, DE
• Albert Heuberger · Erlangen, DE
• Heinz Gerhauser · Waischenfeld, DE
• Rainer Perthold · Weisendorf, DE
• Hartmut Schott · Erlangen, DE

Key dates

• Filing date: Oct 5, 1998
• Grant date: Jun 24, 2003
• Expiry date: Oct 5, 2018

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04H20/31
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

In a coding method and a coder for introducing a non-audible data signal into an audio signal, the audio signal is first transformed to a spectral range and the masking threshold of the audio signal is determined. A pseudo-noise signal and a data signal are provided and multiplied with each other so a to provide a frequency-spread data signal. The spread data signal is weighted with the masking threshold, and thereafter the audio signal and the weighted data signal are superimposed. In a method and a decoder for decoding a data signal introduced into an audio signal in non-audible manner, the audio signal is first sampled and thereafter the sampled audio signal is filtered in non-recursive manner. The filtered audio signal is subsequently compared to a threshold value so as to retrieve the data signal.