20121121SELECTIO

说明：  下面的程序利用友元函数求两点间的距离。请你将有关的程序补充完整，并总结为什么这里要用友元函数来求两点间的距离。(using friend to get the result.)

pic modified sine wave inverter circiut

51单片机考勤系统下位机程序，可以配合上位机软件实现考勤功能，将hex文件下载到51单片机即可使用(51 MCU control procedures can be achieved with the PC software attendance function, the hex file into the microcontroller 51 can be used)

4通道ad7682驱动程序 在msp430单片机上调试成功(4-channel ad7682 driver debugging success msp430 microcontroller)

数字量-模拟量转换器，可以实现单片机处理的数字量信号转换成模拟量电压电流信号输出(Digital analog converter)

交流电动机的矢量控制（Transvector Contrl）理论，从理论上解决了交流电动机转矩的高性能控制问题。其基本思想是在普通的三相交流电动机上设法模拟直流电动机转矩控制的规律，在磁场定向坐标上，将电流矢量分解成产生磁通的励磁电流分量 和产生转矩的转矩电流分量 ，并使两分量互相垂直，彼此独立，然后分别进行调节。这样，交流电动机的转矩控制，从原理和特性上就与直流电动机相似了。因此，矢量控制的关键仍是对电流矢量的幅值和空间位置的控制。(AC motor vector control (Transvector Contrl) theory, control theory to solve the problem of high-performance AC motor torque. The basic idea is to try to simulate the DC motor torque control law in the ordinary three-phase AC electric motor in field-oriented coordinates, the current vector decomposed to produce the excitation current component of the magnetic flux generating a torque current component and torque, and two components perpendicular to each other, independently of each other, and then were adjusted. Thus, AC motor torque control, the principle and characteristics of the DC motor on and similar. Therefore, the key vector control is still the amplitude and spatial position of the current vector control.)

一款电厂巡检软件，很简单的C++处理程序，适合初学者使用，C++(A plant inspection software, very simple C++ handler for beginners, C++)

stm32f072rbt6 直流电机编解码（光栅编码器）的数据采集程序。(stm32f072rbt6 DC codec (coder raster) data collection program.)

智能家居开发智能家居的程序代码分享谢谢。觉得好用的就下载玩玩(Intelligent development of intelligent Home Furnishing Home Furnishing code share. Feel good just download and play)

该程序是CRC校验程序，可以查看文件的校验和，这对文件本身进行校验，也可用在其它程序中检难数据正确与否(CRC procedures can view the document and check that the document itself calibration, but also can be used in other programs Frederick hard data are correct or not)