Reserach And Implementation Of Coaxial Signal Transmission Platform On RF Direct Sampling

With the development and combination of television networks, telecommunication networks and Internet, it is the main opportunities and challenges for the next Generation Broadcasting to quickly improve the cable television network to two-way data transformation.Currently, most coaxial cable network access systems use 1024QAM-OFDMA as modulation technique, it can provide the spectral efficiency of 7bps/Hz with 100 M physical layer data rate. All of these severely limit the HD video, broadband data access and other services. Moreover it is not conducive of the existing access systems to adapt the complex environment by using the fixed transceiver frequency.For the practical issues, the paper research and implement a coaxial signal transmission platform based on the EPoC standards with the idea of software defined radio technology.Firstly, it researches the 4096QAM-OFDMA modulation of core networking technology on EPoC system, then abstract the actual networking scene to laboratory testing environment. And also study the typical implementation of software radio technology.Secondly, it makes a research on the RF direct sampling techniques, especially the Dual-Edge Sampling of ADC and the selectable frequency-response output of DAC, research and implement a coaxial signal transmission platform on RF direct sampling to suit the issue. The signal bandwidth and the number of sub-channels can be configured, and the center frequency can be deployed form 5 to 1536 MHz. The SNR of digital front end loop is up to 44 dB.Finally, it builds a laboratory environment to test the performance on a actual networking scene, the EVM of digital front end loop is less than 0.7%. When transformed through the 100 m coaxial network, the EVM of full loop is less than 1%. The platform achieved the 4096QAM-OFDMA modulation on FDD mode.The paper provides a platform to achieve coaxial signal transmission on RF direct sampling, and has been verified by all the performance to test the design specifications. It contributes to the development of EPoC standard research in China.