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Method for reduction of aliasing introduced by spectral envelope adjustment in real-valued filterbanks

  • US 20040117177A1
  • Filed: 08/29/2003
  • Published: 06/17/2004
  • Est. Priority Date: 09/18/2002
  • Status: Active Grant
First Claim
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1. Apparatus for spectral envelope adjustment of a signal, comprising:

  • means for providing a plurality of subband signals, a subband signal having associated therewith a channel number k indicating a frequency range covered by the subband signal, the subband signal originating from a channel filter having the channel number k in an analysis filterbank having a plurality of channel filters, wherein the channel filter having the channel number k has a channel response which is overlapped with a channel response of an adjacent channel filter having a channel number k−

    1 in an overlapping range;

    means for examining the subband signal having associated therewith the channel number k and for examining an adjacent subband signal having associated therewith the channel number k−

    1 to determine, whether the subband signal and the adjacent subband signal have aliasing generating signal components in the overlapping range;

    means for calculating a first gain adjustment value and a second gain adjustment value for the subband signal and the adjacent subband signal in response to a positive result of the means for examining, wherein the means for calculating is operative to determine the first gain adjustment value and the second gain adjustment value dependent on each other; and

    means for gain adjusting the subband signal and the adjacent subband signal using the first and the second gain adjusting values or for outputting the first and the second gain adjustment values for transmission or storing.

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