说明：  PWM原理 2、调制器设计思想 3、具体实现设计 一、 PWM（脉冲宽度调制Pulse Width Modulation）原理： 脉冲宽度调制波通常由一列占空比不同的矩形脉冲构成，其占空比与信号的瞬时采样值成比例。图1所示为脉冲宽度调制系统的原理框图和波形图。该系统有一个比较器和一个周期为Ts的锯齿波发生器组成。语音信号如果大于锯齿波信号，比较器输出正常数A，否则输出0。因此，从图1中可以看出，比较器输出一列下降沿调制的脉冲宽度调制波。
(PWM principle 2, modulator design ideas 3, concrete realization of the design 1, PWM (Pulse Width Modulation Pulse Width Modulation) principle: Pulse-width modulation wave is usually a rectangular pulse duty cycle of different composition, its duty cycle and the signal is proportional to the instantaneous sampling value. Figure 1 shows the pulse-width modulation system block diagram and waveform diagram. The system has a comparator and a cycle composed of Ts of the sawtooth generator. If the voice signal is greater than sawtooth signal, the comparator output of the normal number of A, otherwise output 0. Thus, as can be seen from Figure 1, the comparator output a falling edge pulse width modulation wave modulation....)