The present invention relates to coding of audio signals, and in particular to high frequency reconstruction methods including a frequency domain harmonic transposer. A system and method for generating a high frequenc...
标准号:
US9830928(B2)
The present invention relates to coding of audio signals, and in particular to high frequency reconstruction methods including a frequency domain harmonic transposer. A system and method for generating a high frequency component of a signal from a low frequency component of the signal is described. The system comprises an analysis filter bank (501) comprising an analysis transformation unit (601) having a frequency resolution of Δf;and an analysis window (611) having a duration of DA;the analysis filter bank (501) being configured to provide a set of analysis subband signals from the low frequency component of the signal;a nonlinear processing unit (502, 650) configured to determine a set of synthesis subband signals based on a portion of the set of analysis subband signals, wherein the portion of the set of analysis subband signals is phase shifted by a transposition order T;and a synthesis filter bank (504) comprising a synthesis transformation unit (602) having a frequency resolution of QΔf;and a synthesis window (612) having a duration of DS;the synthesis filter bank (504) being configured to generate the high frequency component of the signal from the set of synthesis subband signals;wherein Q is a frequency resolution factor with Q≧1 and smaller than the transposition order T;and wherein the value of the product of the frequency resolution Δf and the duration DA of the analysis filter bank is selected based on the frequency resolution factor Q.
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