| 摘要 |
PURPOSE:To eliminate the need for complicated function calculation and for provision a table storing in advance nonlinear functions by calculating a coefficient in nonlinear relation to a characteristic of the filter in a way of approximating to one polynomial or over. CONSTITUTION:An input signal of a filter DF1 is fed to one input terminal of an adder A, and an output signal of the adder A1 is fed to a multiplier input terminal of a multiplier M2 and a delay input terminal of a delay element Z<-1>. The output signal from the delay element Z<-1> is given to the multiplier M1 in which a coefficient beta is multiplied with the signal and the product is fed back to another input terminal of the adder A1. On the other hand, a signal fed to a multiplier input terminal of the multiplier M2 is multiplied with a coefficient a and the result of multiplication is outputted externally as an output signal of the digital filter. Thus, each coefficient of a discrete transfer function of the digital filter, especially a coefficient including a nonlinear function term is approximated by one polynomial or more not including an exponential function and a trigonometric function. |
