How to Choose a Video Matrix Switcher?
1. The introduction of video matrix switcher
The switching principle of video matrix switcher is basically the selection. There are many ways to select, and the easiest is to directly connect the signal wires together. The second method is to use the relay. The on-off of the relay can be controlled by the level, which can complete the disconnection and connection between the output and the input signal, and the selection of the signal. The third method is based on the circuit. The principle is to use the on-off of the internal circuit of the chip to switch on-off, and can control the level to complete the selection of the signal.
2. The technical indicators of the video matrix switcher
Video matrix switchers require different technical indicators according to different application fields. Taking the broadcasting industry as an example, in order to ensure the display quality of the terminal, it assigns technical indicators throughout the entire signal transmission process, from the camera to the TV.
For the switching and distribution of analog matrix, the technical indicators set are as follows: GB/T14236-93 instance index generally refers to the case of multiple inputs with multiple output options to form the matrix structure. And the structure formed by M×N is called matrix switcher, the M×1 structure called switcher or selector while the 1×M structure called a distributor. The principle of the matrix is to use the internal circuit to turn on and off, and can be controlled by the level to complete the signal selection.
3. The size and type of video matrix switcher
In a project, the signal of audio, video, and VGA should be regarded as three different media. Audio signals are generally input in a large number, such as microphones, CDs, and audio from disc players. However, considering that there is ususally only one set of power amplifiers and speakers, at most, a mixer is added before the power amplifier for mixing, so it may needs several signals. Therefore, the output of the video matrix switcher will not be very large, such as 32×8 or 64×8, but there is no need to choose 32×32 or 64×64. Unless it is broadcast and video conference transmission, each channel will certainly have sync transmission.
Video matrix switcher in the design of the project, the number of signal sources is relatively easy to determine. See how many signal sources there are, and the number of inputs to the matrix is determined, but the number of independent output channels must be considered, which is based on the operation mode of the system. Sometimes there may be only a distribution relationship between several display devices (always consistent with each other, not independent), then you can consider occupying an output port and adding a distributor. If these devices may be independent, then it's better to have a separate output port for each.