An algorithm for interpolation at real frequencies with a minimal reactance function by the discrete Chebyshev approximation method

An algorithm for interpolation on the real frequency axis with a reactance function of minimal degree is presented. It becomes operative after the minimal representation (P,Q) of the associated Z/sub RC/ interpolation problem, obtained by an algorithm initiated by V. Belevitch (1970), turns out not to be a Z/sub RC/ interpolant. The algorithm consists of two parts: (1) an initial checking program, based on certain properties of Z/sub RC/ functions, which sets a lower bound on the location of the minimal interpolant in a specified hierarchy; and (2) a systematic search program, based on the discrete Chebyshev approximation, which indicates the existence of the sought-after minimal interpolant and provides a procedure for its construction.<>