数字电视复分接系统

The transport system of digital television

本文从数字电视系统的结构层次入手 ,剖析了复分接系统的组成 ,着重阐明了复分接系统在系统同步建立、音视频信号唇音同步 (LipSync .)、条件接收 (ConditionalAccess,简写为CA)功能的实现、保证系统后向兼容、提高系统抗误码性能等方面的工作机理 ,并计算了MPEG - 2传送系统的同步性能参数 ,如平均同步持续时间、平均失帧时间、平均确认失帧时间及平均搜捕时间等。

In this paper,first we look into the structure of transport system in digital television,then we describe the mechanisms which the transport system provides on system clock recovery,audio/video synchronization,realization of conditional access and backward compatibility,as well as the association with the channel codec to improve the system′s performance of error correction and detection.Finally we calculate the synchronization performance parameters such as T 1,T r,T d,etc.