Abstract: Poles and zeros of the transfer function play an decisive role for filter performance.For an all-pole filter,the transmission zeros(attenuation poles) are all located at infinite frequency and dc.Finite transmission zero locations can be used to realize special features such as quasi-elliptic(real frequency zeros)response,equalized delay,i.e.linear phase(real axis or complex zeros).Some of the important concepts for network synthesis are analyzed which considered as a good summary of those formulated in several classic references.Pole&zero pattern comparison of some typical transfer functions is given,as well as some useful design examples using pole&zero locating technique.