초록 ▼

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

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.

대표청구항 ▼

[ We claim:] [1.] A method for transporting auxiliary information in an audio signal, comprising the steps of:modulating a pseudorandom noise carrier by said auxiliary information to provide a spread spectrum signal carrying said information on a carrier portion thereof;evaluating said audio signal

[ We claim:] [1.] A method for transporting auxiliary information in an audio signal, comprising the steps of:modulating a pseudorandom noise carrier by said auxiliary information to provide a spread spectrum signal carrying said information on a carrier portion thereof;evaluating said audio signal using time domain modeling to obtain an approximation of its spectral shape; andusing time domain synthesis responsive to said time domain modeling to provide a synthesis filter; andinputting said spread spectrum signal to said synthesis filter to spectrally shape the carrier portion of said spread spectrum signal to simulate the spectral shape of said audio signal, thereby producing a colored noise signal containing said auxiliary information to be carried in said audio signal.