脉冲宽度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-Pulse width modulation is a very effective technique to control the analog circuit by the digital output of the microprocessor. It is widely used in the measurement, communication and power control and transformation.