| 摘要 |
PURPOSE:To ensure approximation for desired amplitude characteristics or phase characteristics on the nonlinear frequency scale such as a mel scale, and at the same time to secure a quick countermeasure to a desired characteristic change, by attain a polynomial which is divided into a constant term and a term containing a factor of a variable to a delay element. CONSTITUTION:A specific equation is deformed to an equation which is divided into a term containing a variable z<-1> corresponding to a unit delay element as a factor and a term which does not contain said variable. Thus a digital filter is obtained. The figure shows the circuit diagram of the digital filter, where A is an adder/subtractor, z<-1> is a unit delay element, HA(z) is a primary full band pass filter, and alpha, bm and exp(b0) are coefficient devices respectively. In such a way, it is possible to have satisfactory approximation of the desired frequency characteristics on the nonlinear frequency scale with a comparatively simple constitution. |
