Study of system requirements for digital cable television with experiments

Abstract

The Cable Television Conference working group conducted experiments on the 64 QAM signal transmission in a CATV system from 1995 to 1996. These experiments were based on the tentative specifications of the Telecommunications Technology Council of the Ministry of Posts and Telecommunications (MPT), to promote standardization of the Japanese digital CATV system. Experimental results showed that a C/N of more than 26 dB, a Composite Triple Beat (CTB) of less than -43 dB, and a single carrier interference of less than -30 dB were required to keep a BER of less than 1×10-4 without forward error correction. Cable reflection within the conventional CATV standard for NTSC-AM signals was low enough for 64 QAM signals. Experiments on adjacent channel interference between 64 QAM and NTSC-AM signals indicated that the 64 QAM signal level needed to be lower than the NTSC-AM signal level by about 4-20 dB. Based upon these results, the Japanese standard was introduced by MPT on December 3, 1996.