Patent ID: 7940842
Filing Date: 2011-05-10
Classification: H03G,H04S

Abstract:
1. A method for decoding an encoded BTSC composite audio signal comprising: digitally separating a L−R signal and a L+R signal, both being encoded in the composite signal; digitally applying deemphasis to the L+R signal; digitally processing the L−R signal, wherein the step of digitally processing includes computing spectral expansion coefficients and using said coefficients to spectrally expand the L−R signal into a spectrally expanded output signal, wherein the coefficients for spectrally expanding the L−R signal are determined based on a band-limited feed-forward compressed L−R signal, and wherein a reciprocal of the RMS value of the feed-forward signal is used to determine the spectral expansion coefficients; and combining the de-emphasized L+R signal with the digitally processed L−R signal to produce separate I, and R audio signals.