说明：  电子线路 portel 99 画PCB板的祥细讲解，包括工具条的使用，原理图编辑，原理图元器件编辑，PCB板布线，PCB元器件编辑，信号仿真等全部功能讲解
(PCB electronic circuit board picture portel 99 Xiangxi explanations, including the use of toolbars, schematic editor, schematic editor components, PCB board layout, PCB components, editing, signal simulation, and all functions explained)