tailieunhanh - DSP A Khoa học máy tính quan điểm P11

Biological Signal Processing At first it may seem a bit unusual to find a chapter on biological signal processing in a book dedicated to digital signal processing; yet this is in reality no more peculiar than motivating DSP by starting with the analogous principles of analog signal processing. Indeed the biological motivation should be somewhat closer to our hearts (or eyes, ears and brains). In this book we have chosen to introduce analog and digital signal processing together, but have confined our discussion of biological signal processing to this chapter | Digital Signal Processing A Computer Science Perspective Jonathan Y. Stein Copyright 2000 John Wiley Sons Inc. Print ISBN 0-471-29546-9 Online ISBN 0-471-20059-X 11 Biological Signal Processing At first it may seem a bit unusual to find a chapter on biological signal processing in a book dedicated to digital signal processing yet this is in reality no more peculiar than motivating DSP by starting with the analogous principles of analog signal processing. Indeed the biological motivation should be somewhat closer to our hearts or eyes ears and brains . In this book we have chosen to introduce analog and digital signal processing together but have confined our discussion of biological signal processing to this chapter. In the first two sections we examine how we map external signal parameters into internal biological psychological representations. This question belongs to the realm of psychophysics the birth of which we describe. Our senses are highly sensitive and yet have a remarkably large dynamic range we would like to understand and emulate this ability. We will see that a form of universal compression is employed one that is useful in many DSP contexts. The majority of the signals we acquire from the outside world and process in our brains are visual and much interesting signal processing takes place in our visual system. Much has been discovered about the functioning of this system but here we concentrate on audio biological mechanisms since the focus of this book is one-dimensional signals. Hearing is the sense with the second largest bandwidth and speech is our primary method of communications. We will devote a section each to speech production and perception mechanisms. In a later chapter we will study a DSP model of speech production that is based on this simplified biology. After studying the signal input and output mechanisms we proceed to the processing apparatus namely the brain. We discuss the basic processor the neuron and compare its architecture .