LED displays(vms) are broadly employed within the leisure culture square, the bustling commercial base, commercial street, railway stations, subways, purchasing malls and other locations. For the reason that of its use in the field of diversity, complexity, for steady audio and video signal transmission, reliable, fluency is also a greater demand. Transmission implies single-screen playback or network simulcast signal LED show employed with diversification. Common LED show signal into a wired signal transmission cable, GPRS, 3G, 4G as well as other wireless signals.
A, LED display of signal transmission classification
1, the wireless transmission: rely primarily on the frequency on the radio signal to classify various jobs, like long-wave, medium wave, short wave and microwave. Telephone signal is a wireless access method, now a lot of use of mobile phone GSM operating frequency at 900MHz. Tv signal breed, the extra, for example Television: Basic would be the transmission of analog signals, digital Television may be the transmission of digital signals; LED show signals are digital tv signals around the satellite signals.
two, cable transmission: may be divided into analog transmission, digital signal transmission, digital optical signal transmission.
Second, LED (led traffic sign)show significant signal transmission project
Furthermore to signal attenuation, other things affecting the signal transmitted can be a signal reflection. Impedance and impedance mismatch is causing successive two main factors for constituting the signal reflected RS-485 bus. Impedance mismatch, the impedance mismatch in between the impedance in the first 485 chip and communication lines do not match. That gave rise to reflection for the reason that communication lines idle, all communication line signal mess, after these reflected signals trigger input 485 chip contrast, a fault will happen within the signal.
The usual remedy is to A, B line RS-485 bus, plus the resistance of your bias resistor ought to then pulled up and down respectively, this could not predict avoid clutter signal. A series impedance, when the light is reflected from one particular medium into another medium brought on equivalent. Signals the end of your transmission line impedance of the cable all of a sudden encountered small signal will cause the regional reflection. This reflection eradicate the most prevalent solution is at the end of a jumper cable characteristic impedance in the cable and the exact same size from the terminal resistor.
Third, the way to make sure the safety function LED(EN12966) show of signal transmission process
We are able to develop straightforward robust RS-485 communication protocol, when communication distance is short, use from the environment disturb hour, one-way communication function to complete the project, but most of the use of the atmosphere so that is not normally excellent. Therefore, to create a extensive communication protocol is particularly crucial. The distinct measures, the data sub-transfer, immediately after each and every packet information plus header and trailer of the way the information package, throughout the finish of frame leaving a byte as a verify byte. Next crew immediately after their accounts check bytes and Computer transmission more than the verify bytes for comparison, giving Computer announced instruction, in the long run is just the starting to send the packet information is then still issued the following packet information, Such a package then send the following packet completed till completed cease. Following such a check retransmission mechanism, we'll be capable of minimize the probability of error, to ensure that the standard operation of the communication method(speed limit sign).