一引言经过广播电视工作者的多年努力，我国的电视广播覆盖率已近９０％，电视已成为广大人民群众了解国内外大事和娱乐的重要工具。我们为什么还要发展数字电视？主要是数字电视广播在技术上有很多优势：第一，利用数字电视音视频压缩技术，提高频率资源的利用率。第二，提高 I. INTRODUCTION After many years of efforts by radio and television workers, the coverage of television broadcasting in our country has reached nearly 90%. Television has become an important tool for the masses to understand the major events and entertainment at home and abroad. Why do we need to develop digital television? Mainly digital television broadcasting in the technology has many advantages: First, the use of digital TV audio and video compression technology to improve the utilization of frequency resources. Second, improve