Jh. Shin et Bg. Lee, IMPROVED LBR 2-PAIR EXTRACTION METHODS FOR LOW-SENSITIVITY DIGITAL-FILTER REALIZATIONS, IEEE transactions on circuits and systems. 2, Analog and digital signal processing, 44(3), 1997, pp. 226-239
In this paper, we present two improved lossless bounded-real (LBR) two
-pair extraction methods using an allpass input function, which signif
icantly reduce roundoff errors during the extraction process and reduc
e the amount of computation nearly to a half. Both methods are based o
n the induced allpass transfer function from the given BR function, wh
ich is obtained by replacing the value of the terminating multiplier w
ith 1 or -1. The first method is an LBR two-pair extraction based dire
ctly on the allpass input function induced from the given input transf
er function. The second extraction method is based on two new real pol
ynomials obtained by further decomposing the induced allpass input fun
ction. Even with two polynomials, the involved polynomial division and
parameter calculation are simpler in the second method. Consequently,
numerical errors are further reduced in the second method. The benefi
ts of employing the two improved methods are confirmed through simulat
ion examples.