•拉氏变换的定义——从傅立叶变换到拉氏变换 •拉氏变换与傅氏变换的关系 •拉氏变换的性质，收敛域 •卷积定理(S域) •系统函数和单位冲激响应

本章将采用与讨论连续时间完全相同 的思想方法,来研究离散时间周期信号 与非周期信号的频域分解问题。 DFS与CFS之间既有许多类似之处,也有 一些重大差别:主要是DFS是一个有限项 级数,具有周期性

本章将学习建立信号与系统的数学描 述与数学表示,借以研究信号与系统分 析中的基本概念及基本性质,为以后各 章的学习打下基础

基本思路:对LTI系统,由于其具有叠加性,齐 次性,时不变性,故而,如能实现将任意信号在时域分解为 简单单元信号的线性组合,那么只要得到LTI系统对基本 信号的响应,就可以利用系统的线性特性,将系统的输 出响应表示成系统对基本信号的响应的线性组合

Introduction (chapter objectives) Bit error rate for binary systems (unipolar, polar, bipolar, ooK, BPsK, FsK, and MSK Output signal-to-noise ratio for analog systemS(AM, SSB, PM, and Fm)

Introduction (chapter objectives) Power spectral density Matched filters Recall former Chapter that random signals are used to convey information. Noise is also described in terms of statistics. Thus, knowledge of random signals and noise is fundamental to an understanding of communication systems

5. Introduction (Chapter objectives) Amplitude modulation and single sideband Frequency and phase modulation Digitally modulated signals(OoK, BPSK, FSK, MSK MPSK, QAM, QPSK, a/4QPSK, and OFDM) Spread sprectrum and CDMa system

Introduction (chapter objectives) Complex envelopes and modulated signals Spectra of bandpass signals Nonlinear distortion · Communication circuits(mixers, phase- locked loops, frequency synthesizers, and detectors) Transmitters and receivers · Software radios

3.9 Time-Division Multiplexing Definition. Time-division multiplexing (TDM) is the time interleaving of samples from several sources so that the information from these sources can be transmitted serially over a single communication channel

Chapter Objectives Analog-to-digital signaling(PCM and delta modulation) Binary and multilevel digitals signals Spectra and bandwidths of digital signals Prevention of intersymbol interference Time division multiplexing Packet transmission