Digital realization of complex transfer functions

Abstract

The need for realizing an arbitrary complex transfer func tion often arises in digital or hybrid simulation. A method for the optimal design of the digital implementation (equiv alent to a tapped delay line) of such transfer functions is presented. This procedure finds application in both purely digital and closed-loop hybrid simulations. In the latter case, the digital computer extends the capability and ca pacity of the analog computer and provides an efficient realization of complex transfer functions. Since the sampling frequencies for most simulations are run above the Nyquist rate, the procedure is designed to ignore the higher frequencies where signal energy is ab sent. In this fashion an optimum match to the desired characteristic can be achieved in the frequency band of interest. The procedure can fully compensate for degrada tions introduced by the hybrid sample-hold and recon struction method.