Patent ID: 6226616
Filing Date: 2001-05-01
Classification: G10L,G11B,H04B

Abstract:
A multi-channel audio encoder for coding a digital audio signal sampled at a known sampling rate and having an audio bandwidth, comprising:a core encoder having a sampling rate and audio bandwidth less than that of said digital audio signal;an extension encoder having a sampling rate and audio bandwidth equal to that of said digital audio signal;a decimation low pass filter (LPF) that filters the digital audio signal to remove signal components above the audio bandwidth of the core encoder;a decimator that down samples the filtered signal to extract a core signal whose sampling rate matches the core encoder, wherein said core encoder codes the core signal into core bits;a core decoder that decodes the core bits to form a reconstructed core signal;an interpolator that upsamples the reconstructed core signal to the extension encoder sampling rate;an interpolation LPF that filters the upsampled reconstructed core signal to remove interpolation aliasing; anda summing node that subtracts the filtered signal from the digital audio signal to form a difference signal, wherein said extension encoder encodes the difference signal into extension bits.