Patent ID: 6052658
Filing Date: 2000-04-18
Classification: G10L

Abstract:
A coding method based on Bark spectrum said coding method comprising:modeling amplitudes of a speech spectrum by using a harmonic wave modeling to obtain a speech waveform;transferring said speech waveform from a frequency spectrum to a Bark spectrum to obtain Bark parameters using a Bark-to-Hz transformation;integrating said Bark parameters to obtain a frequency response of an excitation pattern using a critical-band integration;transferring said frequency response to a loudness by using an equal-loudness pre-emphasis;transferring said loudness to a subjective loudness;quantizing said subjective loudness to obtain quantized subjective loudness using a pulse coding modulation (PCM);transferring said quantized subjective loudness to said subjective loudness using an inverse pulse coding modulation;transferring said subjective loudness to said loudness;transferring said loudness to obtain said excitation pattern using an equal de-emphasis;transferring said Bark spectrum to said frequency spectrum;achieving a harmonic wave frequency and amplitude by using pitch and voicing probability, wherein an input energy (.vertline.X(f).vertline..sup.2) of said coding method is equal to .vertline.X(Y(b)).vertline..sup.2, whereas an output D(b) of critical band filters is equal to F(b)*.vertline.X(Y(b)).vertline..sup.2, wherein said Y(b) is referred to a relationship from the Bark b to the frequency f, wherein said F(b) is referred to filters, andY(b)=f=600 sinh[(b+0.5)/6]Hzb=Y.sup.-1 (f)=6 ln{(f/600)+[(f/600).sup.2 +1].sup.1/2 }-0.5 Bark;wherein said output D(b) of said critical band filters presented in a matrix form is: ##EQU13## wherein said f.sub.i, j =F(Y.sup.-1 (j*f.sub.s /N)-i), wherein said f.sub.s is the sampling frequency, wherein said N is the length of FFT, wherein said B is the number of said critical band filters;assuming there is no overlap between said critical band filters, wherein said output D(b) of said critical band filters presented in a matrix form is: ##EQU14## wherein said b.sub.i =Y(i+0.5)* N/f.sub.s.