Patent ID: 7003119
Filing Date: 2006-02-21
Classification: H04S

Abstract:
1. A system for processing a stereo input signal which includes center information, matrix encoded surround information, and stereo information, the system comprising: first circuit for providing a center output having center monaural information, which includes a first summer which combines one channel of the stereo input signal with the other channel of the stereo input signal to form a center combined signal which has the surround information removed; second circuit for providing a surround output from the matrix encoded surround information having surround monaural information, which includes a second summer which combines one channel of the stereo input signal with an inverse of the other channel of the stereo input signal to form a surround combined signal which has the center information removed; third circuit for providing an expanded stereo output, which includes a first Q-filter which adjusts an amplitude and phase of the surround combined signal on a frequency dependent basis to form a first filtered signal; a third summer which combines the center combined signal with one channel of the stereo input signal to form a first signal; a fourth summer which combines the center combined signal with the other channel of the stereo input signal to form a second signal; a fifth summer which combines an inverse of the surround combined signal with the first signal to form the third signal; a sixth summer which combines the surround combined signal with the second signal to form a fourth signal; a seventh summer which combines the first filtered signal with the third signal to form the first output signal; and an eighth summer which combines an inverse of the first filtered signal with the fourth signal to form the second output signal.