Noise during signal transmitting of the display board is reduced by fiber communication system. Electric signal is first translated into optical signal in the output port of this system

and then it is modulated to electric signal in receive port again. The anterior control system all do exchange of electric signals mainly by computers and some large scale integrated circuits

so the frequency is limited by RC delay of wire and the exchange frequency of electronics. In order to make electronic exchange meet the requirement of communication power and little noise

the working velocity of electric chips should be improved greatly

this is too difficult. Now

for electric exchange system

the switch velocity is about 30～50ps

and the velocity of direct signal exchange is about 10～90Mb/s

which is approximately the limitation. For photoelectronic chip

the velocity of switch exchange is about 0.1ps

which has much higher frequency than electric chips. When optical or photoelectronic receive/restore chips are applied in stead of electric ones

the larger wavelength band can be obtained. In addition

optical exchange system can also reduce the working power and noise

and optical exchange system can be used in analog circuit transmit and digital circuit transmit. Fiber amplifier used in the display board

as a kind of optical exchange chip

is nonlinear fiber amplifier

which translates digital image signal and control signal of computer into optical signal. Signals are transmitted to the terminal (display board)

and then they are translated into electric signal again. When the optical signal from fiber input port is amplified

the transmit will be nonlinear

which is not advantaged for transmit

but just because of this

it can be made fiber amplifier. The fiber used in display board is single mode one

which has less power loss

larger wavelength band. So the transmit distance is longer when using single mode fiber. Single mode fiber needs an excellent light source

which should be pure and steady

and has a narrow spectrum density and a much power. For display board

a indoor or outdoor product

safety is also very important

because there is static electricity in the terminal. So when someone checks this system

he might meet much trouble

even damage some parts. By fiber communication

these problems can be improved.