LED large screen signal transmission Detailed

With the continuous development of led strip LED display technology in the field of indoor meeting hall, stage, road traffic, outdoor advertising, etc. The range is more extensive, outdoor LED display. Because of the diversity of its applications, the complexity of the audio and video signal transmission stability, reliability, fluency also put forward higher requirements. Single screen play, also, or network simulcast signal transmission LED display LED display occasions also used to diversify the common LED display signal into a wired signal transmission cable, GPRS, 3G, 4G
">wireless signal wireless transmission.

">A large screen LED signal transmission Category:

1, the wireless transmission: mainly rely on the work of a different frequency radio signals to classify, such as long-wave, medium wave, short wave and microwave. Phone signal is a wireless access, mobile phones are now widely used in GSM operating frequency of 900MHz, commonly known as 900 trillion.
">TV signal type for more, such as cable TV: Normal is the transmission of analog signals, digital television is the transmission of digital signals; television signals are digital signals on the satellite.

">2, the wired transmission: analog signal can be divided into transmission, digital signal transmission, the digital optical signal transmission.

Second, LED large screen signal transmission projects: In addition to the signal attenuation addition, another factor affecting the signal is transmitted signal reflections. Impedance mismatch and impedance discontinuities led to two main reasons RS-485 bus signals reflected form. Impedance mismatch, the impedance is the impedance mismatch between the main chip 485 does not match with the communication line. The reason is because the reflection caused by the communication line is idle, the entire communication line signal disorganized, once these reflected signals triggered 485 chip comparator input, it will generate an error signal. Our usual solution is to A, B wire RS-485 bus with a certain resistance bias resistor, and then were pulled and pulled, so to avoid unpredictable clutter. Impedance discontinuity, when the led strips is reflected from one medium into another medium caused similar. Signal at the end of the transmission line impedance of the cable suddenly encountered small, will cause signal reflection in this place. ">This reflection eliminate the most common method, the end of the cable is the same size across the termination resistor and the characteristic impedance of the cable.
Third, how to ensure the safety of large screen LED signal transmission process: we can develop a simple and reliable RS-485 communication protocol, when the communication distance is shorter, the application of environmental interference hour, one-way communication will be able to achieve the project features, but most applications This environment is not always so perfect. Thus, the development of a comprehensive protocol is particularly important. The specific method, the data sub-transmission, each packet of data by adding header and trailer way data package, which left one byte frame tail as parity bytes. Under his crew calculated by comparing it with the checksum byte transmission over PC checksum byte, which issued a directive to the host computer, in the end was just re-send the packet data or packet data is then issued to the next, so a pack finished recurrence next packet until the far end. ">Such a check through retransmission mechanism, we can reduce the probability of error, making the communication system to normal operation.
In short, the signal transmission process, and reduced with increasing distance. Therefore, in order to ensure playback LED display, LED display reflects the spread relative to other advertising methods, choose the flexible led strip LED display of the transmission medium is especially important.