脉冲宽度调制(PWM)，是英文“Pulse Width Modulation”的缩写，简称脉宽调制，是利用微处理器的数字输出来对模拟电路进行控制的一种非常有效的技术，广泛应用在从测量、通信到功率控制与变换的许多领域中。

随着电子技术的发展，出现了多种PWM技术，其中包括：相电压控制PWM、脉宽PWM法、随机PWM、SPWM法、线电压控制PWM等

本程序是利用PWM进行DA转换控制

-Pulse width modulation (PWM), the abbreviation of the English " Pulse Width Modulation" , referred to as pulse width modulation, is to use the digital output of the microprocessor to control a very effective technology to analog circuits, widely used from the measurement, communications to power control and transform many areas. With the development of electronic technology, a variety of PWM technology, including: phase voltage control PWM, pulse width PWM method, random PWM, SPWM method, line voltage control PWM procedures is the use of PWM DA converter control