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

  • US 7,590,543 B2
  • Filed: 09/21/2007
  • Issued: 09/15/2009
  • Est. Priority Date: 09/18/2002
  • Status: Active Grant
First Claim
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1. Apparatus for calculating gain adjustment values for gain adjusting a plurality of audio subband signals generated by filtering an audio signal using an analysis filterbank, the analysis filterbank having subband filters, adjacent subband filters of the filterbank having transition bands overlapping in an overlapping range, comprising:

  • an examiner for examining an audio subband signal originating from a subband filter and an adjacent audio subband signal originating from an adjacent subband filter, to determine whether the audio subband signal and the adjacent audio subband signal have aliasing generating signal components in the overlapping range to obtain grouped audio subband signals in response to a result of the examination indicating that the audio subband signal and the adjacent audio subband signal have aliasing generating signal components in the overlapping range;

    a calculator for calculating a first gain adjustment value and a second gain adjustment value for the grouped adjacent audio subband signals, wherein the calculator is operativeto determine an indication of a reference energy for the grouped audio subband signals and an energy estimate for an energy in the grouped adjacent audio subband signals, andto calculate the gain adjustment values for the grouped audio subband signals based on the indication of the reference energy and the energy estimate.

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