MMDS Television Coverage System

详情

System advantage

1. QPSK modulation is suitable for single transmitter and broadband transmitter. 
2. Standard CA system is with DVB Public Scrambling Algorithm. Support the same password running. 
3. CA system could be compatible with and DVB standard and hardware. 
4. Descrambling CA module set-top box can be embedded in the receiver which is user-specified criteria in line with DVB. 
5. Adopt digital satellite set-top box, the product is mature and reliable. 
6. Very low receiving threshold, it is easy to install for users. 
7. Superior error correction capability, error rate is very low, receive stable and reliable. 
8. In accordance with accounting programs, achieve value-added services classification (such as adult programs, film programs are charged different rates, the user may choose program, operators can be given only to certain types of programs to allow the privilege of watching the crowd). 
9. The realization of charges intelligent, smart card is authorized and the user credit card payment initiative. 
*0. Transmit encrypted digital TV program, image quality is up to DVD. 
*1. Adopt independent scrambler. It could be used matching with any CA system which is with the standard of DVB. It lay the foundation for fully digitized system. 
*2. System upgrade smoothly, it could achieve multi-functional operations (such as IP, VOD, etc. ). 

Design Idea

1. System stability
2. Signal stability
3. Coverage radius
4. Input cost control
5. System extended and upgraded
6. Standardization

General design

According the requirement listed above, microwave digital television platform include these parts listed as following: 
1. DVB digital TV transmission system
2. Conditional Receiver System
3. User Management System
4. Digital microwave transmission system

Programs and bandwidth planning

A frequency point and bandwidth of *0MHz to a net bit rate transmission: *0/1.*5***8/**4*7/8*2=*2Mbps
Which: Roll-off factor: 0.*5, RS coding rate: **8/**4, Coding rate of convolution codes: 7/8, QPSK rate: Symbol rate * 2
The integrated programs of coding programs adopt rate of 3~6M as usual, a frequency point and bandwidth of *0MHz transmit 7 ~ *3 sets of programs. 
The system has a total of five frequency points. It can transmit a total of *5 sets of digital television programs. Each channel transmits EMM and ECM information, and all programs are scrambled.