Pulse width counting method is to compare the grayscale signal from binary image that stored in the latch, with the value in the counter. The counter and comparator control the duty cycle of the pulse in order to modulate the grayscale signal. 脉宽计数法是将保存在锁存器中的二进制图像的灰度信号,与计数器中的数值通过比较器比较,由计数器和比较器来控制脉冲的占空比,从而达到调制灰度信号的作用。