课堂版chap4.ppt

Chapter 4 Fourier Transform -1 0 1 2 3 t Example 4 Consider a signal with Fourier Transform Evaluate the following frequency-domain expressions: Chapter 4 Fourier Transform Chapter 4 Fourier Transform §4.4 The Convolution Property ( ) ( ) ( ) w w w j H j X j Y = Chapter 4 Fourier Transform LPF filter Series Systems Chapter 4 Fourier Transform Example 4.15 Example 4.16 Chapter 4 Fourier Transform This is an unstable system. Example 4.17 Chapter 4 Fourier Transform Example 4.18 1. Ideal LPF filter Chapter 4 Fourier Transform 2. Causal LPF filter Chapter 4 Fourier Transform The usefulness of the Convolution Property Example 4.19 Solution Chapter 4 Fourier Transform Example 4.20 Chapter 4 Fourier Transform The Fourier Analysis of periodic signals 例 图1所示的LTI系统中，子系统的频率响应分别如图2和图3 所示。 ⑴ 试求整个系统的频率响应； ⑶ 若输入信号 ，试求系统的输出。 + - 图1 图2 图3 Chapter 4 Fourier Transform Chapter 4 Fourier Transform §4.5 The Multiplication property (modulation property) （调制特性） Chapter 4