Patent ID: 7340497
Filing Date: 2008-03-04
Classification: G06F

Abstract:
1. A signal processing device comprising: a first transform unit for decoding a first code string produced by coding a first spectrum signal obtained by performing a direct modified discrete cosine transform on a time series signal, and transforming the first spectrum signal obtained by the decoding into a time series signal by performing an inverse modified discrete cosine transform; and a second transform unit for transforming the time series signal output from said first transform unit into a second spectrum signal by performing a direct modified discrete cosine transform and coding the second spectrum signal into a second code string, wherein, upon generation of a signal band of said second code string narrower than that of said first code string, said first transform unit performs a fast Fourier transform computation to be carried out for said inverse modified discrete cosine transform, using a tap length corresponding to said narrowed band, to increase computational speed and reduce computational storage of the fast Fourier transform of the time series signal.