Tests and Analyses Preliminary to Identification Experiment

Introduction

Like most types of analysis, the application of the white-noise method for the characterization of a physiological system can become very difficult and involved if not preceded by considerable preliminary analysis of the system characteristics and the tools available for its study. In addition, the amount of difficulty depends on the nature of the system nonlinearities and the degree of accuracy which we require from the derived characterization (model). In certain cases the application of the method to a physiological system could produce poor results after long experimental procedures and digital computations. Therefore, it is desirable to develop preliminary criteria and simple experiments and tests that give an indication of how complex the system is and how successful the white-noise method will be in each particular case.

In developing these criteria and tests we shall take into account the characteristics of the system and the experimental limitations inherent in its study by stimulus—response experiments. This is especially important in the study of such physiological systems for which the measurement and even the choice of input and output is a difficult task (e.g., neural systems).