Apparatus and method for encoding and decoding information in audio signals
US6005501A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 26, 1998 |
| Grant date | Dec 21, 1999 |
| Priority date | — |
| Expiry date | May 26, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04H20/31
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus encodes and decodes machine readable signals in audio signals for producing humanly perceived audio transmissions. The encoding device includes circuitry for identifying portions of the audio signal having relatively low energy in a given band and relatively high energy in a band proximally below the given band. The machine readable signals are then inserted into the identified portions of the audio signal. According to another embodiment, the machine readable signals are encoded as a spread-spectrum signal which is added to the original audio signal. The spread-spectrum signal is scaled using a unique technique referred to as Common Mode Scaling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.