Comparison between Chebyshev and power series expansion functions for interpolating data

A study is made of the relative advantages and disadvantages of using power series and Chebyshev polynomials to obtain a rational function representation of the data. This rational function must satisfy both the stability and passivity criteria. The procedures used for obtaining the rational function representation using both Chebyshev polynomials and power series is outlined in the paper. Three test cases have been used to compare the relative performance of the power series and Chebyshev polynomials.