And pays emphasis on analyzing the system structure and system flow , the core techniques , the channel characteristic and parameters of dvb - t system . the system adopts some core techniques such as cofdm , a lot of tps ( transmission parameter signalling ) insert and guard interval , and so on . so it can withstand high - level ( up to odb ) , long delay static and dynamic multipath distortion 论文首先描述了数字电视地面广播的需求条件，技术难点和目前存在的问题，并重点分析了dvb - t系统结构流程，核心技术及系统信道特性和参数，该系统采用了cofdm (编码正交频分多路复用) ，大量导频信号插入和保护间隔技术等核心技术，使之能抵抗高电平( 0db ) ，长延时的静态和动态多径失真，有利于数字和模拟电视的混合传输，它的多载波调制模式功能和性能在移动和便携接收、同频网等方面具有独特的优势。
In the operation of the doubly salient permanent magnet ( dspm ) motor , some possible failures can occur , including the wrong connections of three armature windings , the wrong orders of three hall sensors , and the failures of hall sensor signals themselves , that is the hail sensor signal keeps the high level or the low level to be unchanged with the rotor position 摘要永磁双凸极电机运行时，可能会出现以下常见故障：三相绕组线或和三相霍尔连接线的错误接线；霍尔信号自身的故障，即恒为高电平或低电平，其电平不随转子位置变化而变化。
