【摘要】 重点概述了应用于HFC网络终端的数字电视机顶盒的网络接口模块NIU(NetworkInterfaceUnit)的原理 ,给出了两种制式的NIU框图和QPSK与QAM调制在 8MHz带宽内可传送的码率与C/N门限的数据。介绍了PHILIPS公司半导体芯片TDA640 4 /TDA640 5的参数更多还原

【Abstract】 The Principle of network interface unit NIU of digital TV set-top-box used in HFC network terminal is described mainly, NIU frame fig of twosorts of format and transmissible code rate and data of S/N threshold within 8 MHz bandwidth with QPSK and QAM modulation are given , parameter of semiconductor chip TDA6404/TDA6405 of PHILIPS company are introduced更多还原