Design and implementation of 6/12MHz switchable QAM modulator based on DOCSIS 3.0

Author

Ra, Sang-Jung ; Choi, Dong-Joon ; Hur, Namho

Author_Institution

Broadcasting Syst. Res. Dept., Electron. & Telecommun. Res. Inst., Daejeon, South Korea

fYear

2011

fDate

28-30 Sept. 2011

Firstpage

652

Lastpage

655

Abstract

In this paper, we present an efficient design and implementation of downstream QAM modulator for Digital CATV transmission. The Digital CATV transmission system enables the cable operators to offer high-speed multimedia service for Digital CATV subscribers in HFC network. 6/12MHz switchable QAM modulator for Digital CATV transmission is proposed and implemented in field programmable gate arrays (FPGAs). The Modulator, which can be modulate switchable bandwidth (6 or 12 MHz), consists of FEC encoder, a post-forward error correction (FEC) and a digital to analog converter (DAC). We measure the spectrum of QAM modulator output. Measured results show the maximum transmitted error vector magnitude (EVM) of 0.62% (64-QAM/6MHz), 1.05% (64-QAM/12MHz) and 0.69% (256-QAM/6MHz), 1.12% (256-QAM/12MHz).

Keywords

cable television; community antenna television; digital-analogue conversion; field programmable gate arrays; forward error correction; hybrid fibre coax networks; modems; multimedia systems; quadrature amplitude modulation; DAC; DOCSIS 3.0; EVM; FEC encoder; FPGA; HFC network; QAM modulator output; bandwidth 12 MHz; bandwidth 6 MHz; cable operators; digital CATV subscribers; digital CATV transmission; digital to analog converter; downstream QAM modulator; field programmable gate arrays; high-speed multimedia service; maximum transmitted error vector magnitude; post-forward error correction; switchable QAM modulator; switchable bandwidth; Bandwidth; Cable TV; Communication cables; Forward error correction; Quadrature amplitude modulation; Switches; DOCSIS3.0; EVM; cable modem modulator; switchable bandwidth;

fLanguage

English

Publisher

ieee

Conference_Titel

ICT Convergence (ICTC), 2011 International Conference on

Conference_Location

Seoul

Print_ISBN

978-1-4577-1267-8

Type

conf

DOI

10.1109/ICTC.2011.6082680

Filename

6082680