PWM是一种对模拟信号电平进行数字编码的方法。通过高分辨率计数器的使用，方波的占空比被调制用来对一个具体模拟信号的电平进行编码。PWM信号仍然是数字的，因为在给定的任何时刻，满幅值的直流供电要么完全有(ON)，要么完全无(OFF)。电压或电流源是以一种通(ON)或断(OFF)的重复脉冲序列被加到模拟负载上去的。通的时候即是直流供电被加到负载上的时候，断的时候即是供电被断开的时候。只要带宽足够，任何模拟值都可以使用PWM进行编码。

-PWM is an analog signal levels on the digital encoding method. Through the use of high-resolution counters, the duty cycle square wave is modulated to a specific analog signal level coding. PWM signal is still digital because, at any given moment, the full DC supply is either fully (ON), or fully (OFF). Voltage or current source is supplied (ON) or off (OFF) repeated pulse sequence is added to the analog load. Pass the time during which the DC supply is applied to the load, the time off that is when the supply is switched off. Sufficient bandwidth, any analog value can be encoded using the PWM.