Signal Measurement

Abstract

Measurement of physiological signals is the first step in understanding the underlying physiological system. These measurements are based on a tentative model of the system. The measurement model postulates characteristics of the signal of interest that distinguish it from interfering noise. The two main purposes of signal analysis and system modeling in physiology are (a) to reduce the contaminating noise in the observed signal and (bi) to describe the process in terms of a few parameters. Before any manner of noise reduction is performed a conceptual model of the signal necessarily exists in the mind of the observer. It is this model that determines how effectively the “true” signal will be elucidated from the noisy recording. The selection of noise reduction techniques will depend on this conceptual model. Once the signal is cleaned by the noise reduction technique the system may be modeled more exactly in order to obtain parameters that describe it.