On the realization of highly selective networks by low Q-factor stages

This paper presents a method for interchanging a secondorder frequency emphasizing network with high
Q
-factor poles by a more complicated network that consists of several low
Q
-factor stages. The transfer function of this new network approximates in a Chebyshev manner the square modulus of a given transfer function. It is shown that all low
Q
-factor pairs of the poles must coincide. The procedure includes a method for determining the numerator zeros of the approximating transfer function.