| 摘要 |
PURPOSE:To improve the precision of a pulse search by calculating the autocorrelation of impulse responses and making the pulse search by using them. CONSTITUTION:A voice signal X(n) which is applied to an input terminal 10 is supplied to an interpolator 1 and interpolated there. The interpolated voice signal XI(n) is supplied to an LPC analyzer 2, a pitch extracter 3, and a weighting filter 4. The weighting filter 4 finds a voice XIW(n) by auditory correction based upon the interpolated voice signal and a linear predictive filter coefficient and supplies it to a cross-correlation calculator 6. Then, the cross correlation RHX(n) and autocorrelation RHH(n) are supplied to a pulse searcher 8. The pulse searcher 8 searches for pulses by using the cross correlation RHX(n) and autocorrelation RHH(n). Information obtained by the pulse search is supplied to an encoder 9. |
