| 摘要 |
PURPOSE:To find the root of a real coefficient algebraic equation accurately and speedily without fail by constituting the system so that the degree of the algebraic equation is an even degree when the real coefficient algebraic equation is solved by a Bairstow method. CONSTITUTION:An input speech signal X(t) is analyzed by a linear prediction LPC analysis part 11 and predicted linearly so as to minimize a prediction error, and consequently LPC coefficients ai (i=1, 2...P) of P degree defining the transmission function H(z) of P degree obtained by (z) conversion are calculated and sent to a coefficient calculation part 13. Then the preprocessing part 131 of the calculation part 13 sets a P-degree algebraic equation P(z) which includes the coefficients ai from the analysis part 11 and an arithmetic part 132 performs repetitive calculation by the Bairstow method for this equation to obtain the coefficients (v) and (w) of secondary factors of P(z), thereby sending them to a postprocessing part 133. The postprocessing part 133 sends the value of a degree mark K to a root calculation part 14 as it is when the K is 0 and removes a known solution added according to the relation between the coefficient and root and sends the coefficients V and W of the remaining secondary factors when the K is 1. Then the formant frequency F and width B are obtained from the root sent to a formant frequency/band width calculation part 15. |
