The development of digital television is a major event in the field of radio and television in recent years,its arrival has brought prefound technical revolution to the traditonal wireless TV field .It enables the traditional television media and information technology functions gradually, also the other means of communications integration create a new industry structure.The neew digital MMDS wireless transmission can not only provide higher quality images and sound programmes and better efficiency in the use of spectrum, more importantly, it provides a powerful digital television business diversity.

 

Digital MMDS System Principle

Digital MMDS System at first in the core of the channel coding and modulation source on the digital television standard,the modulated signal fed into the system through space launches and space coverage electromagnetic users directly .Image compression according to MPEG-2 standards, each 8 MHz bandwidth compression six sets of television programs, the number of programs increase several times, and the image quality is close to DVD effect, the bandwidth occupied by the 2 / 3,through digital CA system also makes the difficult of charges issues left by history solved and user-friendly management.The digital transmitter coverage radius has greatly increased than analog transmitters under the same power.

 

The specific signals processes of system in general are as follows :

Code development for the transfer of satellite receive provinces digital satellite programs not encrypted , and output TS flow.TS encrypted satellite programs with the use of special decoder output multiplexer output TS flow.Simulation of audio and video signals output TS encoded by MPEG-2 encoder . Local programs audio signals encoded MPEG-2 encoder output TS.Higher figures for the cable network programs, or through adapters demodulator output after TS.TS 6-8 sets of the above programs for one program package, which will become more multi-channel multiplexing TS packages. TS package into independent scrambling aircraft, thereby realizing the power of users' management of CA systems .Scrambling into the TS digital modulator, TS modulated RF channels to enter the launch and feed syste,finally complete the wireless coverage of service area .

 

 

 

 

 

 

 

◆Digital front-end equipment

◆Microwave Transmission Equipment

★ Simulation of point-to-point microwave transmission equipment