05822360 is referenced by 290 patents and cites 12 patents.

Auxiliary data is transported in a conventional audio signal by hiding the data in the form of colored noise. The colored noise has a spectrum that simulates the spectrum of the primary audio signal. The data to be transported is first converted to a spread spectrum signal. The primary audio signal is analyzed to determine its spectral shape. The same spectral shape is imparted to the spread spectrum signal, which is then combined with the primary audio signal for transmission. The spectral shaping can be performed using time domain modeling and synthesis such as linear predictive coding or by using subband coding techniques such as fast Fourier transforms. A plurality of different auxiliary information streams can be transported on the audio signal. By adjusting the gain of individual spread spectrum signal carrier(s) and the power of the colored noise, the auxiliary information stream(s) can be rendered inaudible in the primary audio signal, or at any desired level below or above an audible threshold.

Title
Method and apparatus for transporting auxiliary data in audio signals
Application Number
8/524132
Publication Number
5822360
Application Date
September 6, 1995
Publication Date
October 13, 1998
Inventor
Robert L Warren
Cardiff
CA, US
Kamran Moallemi
Del Mar
CA, US
Chong U Lee
San Diego
CA, US
Agent
Ralph F Hoppin
Barry R Lipsitz
Assignee
Solana Technology Development Corporation
CA, US
IPC
H04B 1/69
H04B 1/707
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