Signal Processing Toolbox™ provides parametric modeling techniques that let you estimate a rational transfer function that describes a signal, system, or process. Use known information about a signal to find the coefficients of a linear system that models it. Approximate a given time-domain impulse response using Prony and Steiglitz-McBride ARX models. Find an analog or digital transfer function that matches a given complex frequency response. Model resonances using linear prediction filters.