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Chongqing terrestrial digital TV system project
 

Chongqing Digital Video Broadcasting-Terrestrial SFN Application & Demonstration Project, approved by the National Development and Reform Committee,  NDT takes charge of the total integration of information source front-end (general front-end) system and information source transmission (including part front-end) system.

1. Information Source Front-end System

 

Information source front-end system mainly receives satellite signals of CCTV and provincial satellite TV programs and coding, multiplex, scrambling and SFN adaption of all broadcast TV programs, including Chongqing city level programs, and provides signal sources to information source transmission systems.

Frame of information source front-end system:

 Equipment Options

The main equipment option of the information source front-end system is Ericsson product including satellite receiver TT1222, H.264 encoder EN8130, multiplexer MX8400, webmaster system nCompass Control, etc. The system chart is as follows:

 

System Characteristics:

 

SDI signal encoding is adopted by the satellite program and local program so as entirely to ensure the signal quality.

Adopting H.264 SD encoding to improve the quality of the image encoding under the same mbps.

The encoder adopts N + M backup and the multiplex adopts 1 + 1 backup to guarantee the system security.

All the major equipments have the main/standby output port, and the main/standby multiplex output increase the switch to further improve the safety.

 

2. Information Source Transmission System

For the early-stage of the Radio and Television Group of Chongqing, a set of NetInsight multicast transmission system has been built up, amounting to 15 stations with the central station adopting Nimbra One and other stations adopting Nimbra 360. According to the transmission demands of the digital video broadcasting-terrestrial signal, the upgrade and extension of the original transmission system will be conducted including replacing the equipment of the central station by Nimbra688 and adding the boards in original sub-station and Nimbra 360 in new sub-station, etc.

 

Multiple channels of ASI signals output by the general front-end are transmitted to each transmitting station through the multicast transmission platform via microwaves. The programs in each district and county, after local encoding, are sent to local transmitting station via optical transceiver, multiplexed and scrambled with a Broadcast Control Channel (BCCH) program steam of general front-end signal, and then they are sent to digital TV transmitters via SFN adapters for the coverage of the programs in district and county.

Equipment Option

 

Information source transmission system is mainly adopting NetInsight networking transmission equipment Nimbra688/360 and 155M transmission board, ASI boards, etc.

 

System Characteristics:

 

The same platform transmits municipal operations, including ASI signal, AES signal, IP signal etc, and it is possible for the future expansion of HD-SDI, SD-SDI signal transmission.

Double routing and loop network routing are protected automatically. When failure occurs in one of the microwave links or the microwave link in a certain direction of the loop circuit, the operation transmission is not affected.

Each operation bandwidth is set adopting 512K time slot, simultaneously sent by the way of multicast to transfer resources using microwave 155M in maximum with the efficient use of bandwidth up to 140M.

Flexible networking and convenient expansion.