介绍一种最新推出的电力载波调制解调器芯片ST7538的基本原理，给出ST7538的主要控制电路和接口电路，讨论应用该芯片后些注意事项。-In this paper，the power line monitor system with stable performance，good reliability and accurate warning has been designed，in which street light monitoring and controlling and electric cable security have been given，using electric power network resources based on low voltage power line carrier