Digital MMDS Is Used On The BCTV Net In Balikun, Xinjiang

MMDS stands for the Multichannel Microwave Distribution System。It is a wireless technology that it may be used for one or more point in information band and supplies for the wide-band of operation .In the last few years, Digital technology is developing. Digital television, wireless transmission net is widely applicable at home and abroad .The basic aim of design decision is digital transmission to carry though and save the maintaining cost. It can be received the functional prototype of high definition picture by users. It can reached and rise the CATV system of the result and coverage areas.This thesis adopts digital MMDS of technology. On the basis of them, according to the specific circumstances in Balikun .To set up a unified service plateau for digital TV, to construct a perfect provincial front system of digital TV, to dispose satellite receiver, Coding and Decoding machine, Multiplexer Scrambler Adaptor etc.CA system, SMS system, to broadcast central and provincial programs as well as satellite digital programs, to send into launching machine for covering wirelessly, which can be received through antenna by users. It transmits digital programs in 2500-2700MHz frequency rang. In the straight received and straight set sending ways, each of channels can be transmitted 6-8 channels on TV programs. The design decision adopts six MMDS sending sets and six integrated power hydrides. It adds up 36-42 programs in order to processes the wireless launching. It is covered with the most of villages in Balikun.The thesis accords to the international standard .In 2503-2687 frequency rang, it arranges radial arrangement 23 channels on TV that it is used for the each of 8 MHz channel wide band ways; . In 2684-2700MHz frequency rang, it can obligate digital,tone of communication,transmission,two way transmission .In 200MHz wide band, it is divided into groups in the Cumby way. A group adopts the odd numbers of channel number. B group adopts the even numbers of channel number .It realizes the expectation aim because it debugs in the radial arrangement way.