METHOD AND APPARATUS FOR EMBEDDING AUXILIARY DATA IN A PRIMARY DATA SIGNAL

摘要

Auxiliary data (x(m)) is transported in a primary data signal (s(t)) by hiding the data in the form of colored noise. The colored noise has a spectrum that simulates the spectrum of the primary data signal. The data to be transported is first converted to a spread spectrum signal d(t). The primary data 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 data signal for transmission. The spectral shaping can be performed using time domain modeling and synthesis such as linear predictive coding (88, 94) or by using subband coding techniques such as fast Fourier transforms (174). A plurality of different auxiliary information streams (280, 290, 300) can be transported on the primary data signal. By adjusting the gain (287, 297, 307, 309) of individual spread spectrum signal carrier(s) and the power (96) of the colored noise, the auxiliary information stream(s) can be rendered at any desired level below or above an interference threshold in the primary data signal.