Burst receiver for upstream communications over twisted pair lines

This paper presents algorithms and implementations of a burst receiver chip for upstream communications over twisted pair lines. The receiver is an all-digital chip, which receives digitized IF QAM signal, and demodulate QPSK, 16-QAM or 64-QAM burst data at 312.5 kbauds. The receiver structure consists of direct digital frequency synthesizer (DDFS), several stages of filtering, burst detection, fast acquiring timing/phase/gain recovery, and adaptive equalizer with fast convergence rate. The receiver is prototyped using programmable FPGA.