Abstract: A system for embedding auxiliary digital information into a primary digital signal to form a composite digital signal. Auxiliary data bits modulate a pseudo-random (e.g., PN) sequence to provide an auxiliary data sequence used to modify the Least Perceptually Significant Bits (LPSBs) of successive multi-bit samples of the primary signal. In a cross-term compensation embodiment, a correlation between the PN sequence and the sample bits is determined, and compared to the auxiliary data bits to determine whether there is a desired correspondence. The LPSBs in the samples are toggled, if necessary, to provide the desired correspondence. The selection of LPSBs to modify accounts for a desired noise level of the auxiliary data in the primary signal. LPSBs may be modified based on a sparse PN sequence to achieve the desired noise level and conceal the presence of the auxiliary data.

Abstract: A system for embedding auxiliary digital information into a primary digital signal to form a composite digital signal. Auxiliary data bits modulate a pseudo-random (e.g., PN) sequence to provide an auxiliary data sequence used to modify the Least Perceptually Significant Bits (LPSBs) of successive multi-bit samples of the primary signal. In a cross-term compensation embodiment, a correlation between the PN sequence and the sample bits is determined, and compared to the auxiliary data bits to determine whether there is a desired correspondence. The LPSBs in the samples are toggled, if necessary, to provide the desired correspondence. The selection of LPSBs to modify accounts for a desired noise level of the auxiliary data in the primary signal. LPSBs may be modified based on a sparse PN sequence to achieve the desired noise level and conceal the presence of the auxiliary data.

Abstract: A system for embedding auxiliary digital information (Di) into an existing primary digitally encoded signal (Xn) to form an unobjectionable composite digital signal (Cn). Auxiliary data bits (Di) modulate a pseudo-random (e.g., PN) sequence (125) to provide an auxiliary data sequence (160) that is used to modify the Least Perceptually Significant Bits (LPSBs) (180) of successive multi-bit samples (120) of the primary signal. In a cross-term compensation embodiment (300, 400, 1000), a correlation (V) between the PN sequence and the sample bits is determined, and compared to the auxiliary data bits (Di) to determine whether there is a desired correspondence. The LPSBs in the samples are toggled (360), if necessary, to provide the desired correspondence. The selection of LPSBs to modify accounts for a desired noise level of the auxiliary data (Di) in the primary signal (Xn).

Abstract: An HDTV receiver takes advantage of the detailed structure of the NTSC signal, namely the periodicity of the signal caused by the horizontal scan rate, in order to remove co-channel interference. A feedforward circuit is used to form an estimate of a current co-channel interference value from co-channel interference values occurring on previous scan lines. The estimate is subtracted from the signal to remove the co-channel interference at the expense of generating intersymbol interference. The circuit uses a form of decision-feedback equalization (DFE) in order to remove the intersymbol interference. The periodicity of the NTSC signal is exploited to allow the use of a high-rate trellis code in the DFE circuit.