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Simultaneous Time-Domain and Frequency-Domain Noise Shaping for TDAC Transforms

  • US 20110145003A1
  • Filed: 10/15/2010
  • Published: 06/16/2011
  • Est. Priority Date: 10/15/2009
  • Status: Active Grant
First Claim
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1. A frequency-domain noise shaping method for interpolating a spectral shape and a time-domain envelope of a quantization noise in a windowed and transform-coded audio signal, comprising:

  • splitting transform coefficients of the windowed and transform-coded audio signal into a plurality of spectral bands; and

    for each spectral band;

    calculating a first gain representing, together with corresponding gains calculated for the other spectral bands, a spectral shape of the quantization noise at a first transition between a first time window and a second time window;

    calculating a second gain representing, together with corresponding gains calculated for the other spectral bands, a spectral shape of the quantization noise at a second transition between the second time window and a third time window; and

    filtering the transform coefficients of the second time window based on the first and second gains, to interpolate between the first and second transitions the spectral shape and the time-domain envelope of the quantization noise.

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