Bandpass transformation and realization using frequency-dependent negative-resistance elements

An -active-network synthesis method described by Bruton for the realization of low-pass filters is extended to the case of bandpass filters. Networks are obtained which use frequency-dependent negative-resistance (conductance) elements as active elements, and these can be realized by using generalized-immittance converters (GICs). In turn, GICs can be implemented by using operational amplifiers. The method is illustrated by designing a sixth-order bandpass elliptic filter; experimental results are also given.