1. One is to centrally manage and control the grayscale of each pixel on the scanning board. The scanning board analyzes and decomposes the gray value of each pixel in the control box, that is, adjusts the pulse width, and then turns on each led network signal in the main form of pulse (lighting is 1 and not lighting is 0), and transmits through serial communication Go to the corresponding conference room LED display, and then control to check whether it can light up. There are few researches on the use of this kind of electronic equipment, but the data of serial data transmission has a greater impact, because this is during its repeated lighting cycle, each target pixel needs 16 pulses at 16 levels of gray. 256 pulses are needed in gray scale. Due to the frequency range limitation of the design working time of these devices, LED screens generally can only reach 16 levels of gray.

2. Pulse width adjustment. The serial transmission of the content scanning board of the LED display in each meeting room is not a switch signal, but a binary 8-bit gray value. Each led has its own pulse width adjuster to control the lighting time. Therefore, in the light repetition period, 16 gray-scale points have only 4 pulses in 256 levels, and each pixel has only 8 pulses, which greatly reduces the frequency of serial transmission. This decentralized gray-scale control light-emitting diode method can easily achieve 256 gray-scale control.