Đang chuẩn bị liên kết để tải về tài liệu:
Digital communication receivers P2 - P1

PART C Baseband Communications Digital Communication Receivers: Synchronization, Channel Estimation, and Signal Processing Heinrich Meyr, Marc Moeneclaey, Stefan A. Fechtel Copyright 1998 John Wiley & Sons, Inc. Print ISBN 0-471-50275-8 Online ISBN 0-471-20057-3 Chapter 2 Baseband Communications 2.1 Introduction to Digital Baseband Communication In basebandcommunication,digital information is conveyedby meansof a pulse train. Digital baseband communicationis usedin many applications,suchas . Transmissionat a few megabitsper second(Mb/s) of multiplexed digitized voice channelsover repeateredtwisted-pair cables . Transmissionof basicrate ISDN (16Okb/s) over twisted-pair digital subscriber lines . Local area networks (LANs) and metropolitan area. | Digital Communication Receivers Synchronization Channel Estimation and Signal Processing Heinrich Meyr Marc Moeneclaey Stefan A. Fechtel Copyright 1998 John Wiley Sons Inc. Print ISBN 0-471-50275-8 Online ISBN 0-471-20057-3 PART C Baseband Communications Digital Communication Receivers Synchronization Channel Estimation and Signal Processing Heinrich Meyr Marc Moeneclaey Stefan A. Fechtel Copyright 1998 John Wiley Sons Inc. Print ISBN 0-471-50275-8 Online ISBN 0-471-20057-3 Chapter 2 Baseband Communications 2.1 Introduction to Digital Baseband Communication In baseband communication digital information is conveyed by means of a pulse train. Digital baseband communication is used in many applications such as Transmission at a few megabits per second Mb s of multiplexed digitized voice channels over repeatered twisted-pair cables Transmission of basic rate ISDN 160kb s over twisted-pair digital subscriber lines Local area networks LANs and metropolitan area networks MANs operating at 10-100 Mb s using coaxial cable or optical fiber Long-haul high-speed data transmission over repeatered optical fiber Digital magnetic recording systems for data storage This chapter serves as a short introduction to digital baseband communication. We briefly consider important topics such as line coding and equalization but without striving for completeness. The reader who wants a more detailed treatment of these subjects is referred to the abundant open literature a selection of which is presented in Section 2.1.5. 2.1.1 The Baseband PAM Communication System Baseband communication refers to the case where the spectrum of the transmitted signal extends from zero frequency direct current DC to some maximum frequency. The transmitted signal is a pulse-amplitude-modulated PAM signal it consists of a sequence of time translates of a baseband pulse which is amplitude-modulated by a sequence of data symbols conveying the digital information to be transmitted. A basic communication system for