OVERSAMPLING IN COMBINED TRANSPOSER FILTER BANK Russian patent published in 2013 - IPC G10L21/02 

FIELD: physics.

SUBSTANCE: 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 D_A; 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 D_s ; 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 D_A of the analysis filter bank is selected based on the frequency resolution factor Q.

EFFECT: high quality of sound by restoring high frequencies of the sound signal by improved harmonic transposition with little additional computational complexity.

25 cl, 12 dwg