Patent ID: 7756715

Claim:
An apparatus for processing an audio signal using a correlation between bands, the apparatus comprising: an encoding unit encoding an input audio signal; and a decoding unit decoding the encoded input audio signal; wherein the encoding unit comprises a correlation analyzer searching a most similar subband having a correlation of more than a predetermined value between first subband and the most similar subband in each of the first subbands from second subbands and generating information about the second searched subband, wherein the decoding unit comprises a high frequency component restoring portion copying data about the second searched subband as data about the first subband, using the generated information about the second subband generated by the correlation analyzer and transmitted in a bit stream format to perform decoding on the first subbands, and wherein the first subbands are subbands that belong to a high frequency band in a band of a result of subband-filtering the input audio signal and the second subbands are subbands that belong to a low frequency band in a band of the result of subband-filtering.