[...]... computing power in recent years has made much of the more complex analysis methodologies possible The purpose of this chapter is to provide an overview of biological signal origins and describe commonly encountered biological signals 1.1 A Typical Biological Signal Analysis Application Before we delve into the analysis of biological signals, it would be useful to understand that they are often represented.. .Biological Signal Analysis Introduction 1 Introduction Biological signal analysis 1 encompasses several interdisciplinary topics that deal with analysing signals generated by various physiological processes in the human body These signals could be electrical, chemical or acoustic in origin and an analysis of these signals are often useful in explaining and/or... (c) Figure 1.15: PCG signals (a) Normal heart (b) Systolic murmur (c) Diastolic murmur 24 Biological Signal Analysis Introduction 1.2.6 Other Biological Signals There are many other biological signals such as arterial blood pressure signals (ABP, shown in Figure 1.16) generated by changes in blood pressure which are recorded on the upper arm (unitsmmHg); electroculogram (EOG) signals, which measure... detection 13 Biological Signal Analysis Introduction 1.2 Examples of Common Biological Signals Commonly encountered biological signals that describe the electrical activity of the brain, heart, muscles etc will be introduced in this section Some of these signals like ECG and electroencephalogram (EEG) are spontaneous activity of the human body while others such as evoked potentials are signals in response... concerned with the aim of analysing biological signals to extract useful information This chapter has introduced some of these biological signals and discussed their origins The methods for signal analysis will depend on the type of the signal and nature of the information being carried by the signal - there are some general methodologies and some specific ones for particular signals The following five chapters... http://www.cs.colostate.edu/eeg/eegsoftware.html#keirndata 27 Biological Signal Analysis Discrete-time signals and systems 2 Discrete-time signals and systems In this chapter, we’ll look at discrete-time signals and systems As described in the first chapter, a signal is a function of independent variables such as time, distance, position, temperature, pressure, etc Most signals are generated naturally but a signal can also be generated... intervals This process is known as sampling9 28 Biological Signal Analysis Discrete-time signals and systems 2.1.1 Sampling Since most biological signals are 1D time series signals10, we’ll focus our attention to such signals where the independent variable is time A discrete-time signal, x[n] is developed by uniformly sampling an analogue signal x(t) as indicated in Figure 2.2 below It is done by taking... representation of t Analogue signal t x[0] x[1] x[18] Figure 2:2: Obtaining a discrete-time signal from analogue signal through sampling 29 Biological Signal Analysis Discrete-time signals and systems 2.1.2 Aliasing Aliasing is a problem in the sampling process as it causes ambiguities in reconstruction, i.e distorts the sampled signal unrepresentative of the original signal To avoid aliasing and be... finite signal y[n] is obtained from a discrete-time infinite signal x[n] using a window, w[n] modulator x[n] X y[n] w[n] Figure 2.5: Product operation 31 Biological Signal Analysis Discrete-time signals and systems 2.3.2 Addittion Addition operation can be performed as given below to add two sequences, y[n] x[n] w[n] (2.3) adder x[n] + y[n] w[n] Figure 2.6: Addition operation 32 Biological Signal Analysis. .. visual evoked potential (VEP) signals While some analysis procedures are common (like using filters to extract components in specific frequency range), the different properties of these biological signals do call for the application of widely varying analysis procedures Hence, it is useful to know the fundamental details of how these signals are generated before studying analysis procedures for extraction . Ramaswamy Palaniappan Biological Signal Analysis Biological Signal Analysis © 2010 Ramaswamy Palaniappan & Ventus Publishing ApS ISBN 978-87-7681-594-3 Biological Signal Analysis 4 Contents Contents . for biological signals and solve practical biological signal analysis problems using MATLAB. Final year undergraduates and graduates students in any field with interest in biological signal. based ectopic beat detection. Biological Signal Analysis 14 Introduction 1.2 Examples of Common Biological Signals Commonly encountered biological signals that describe the electrical