1024-QAM demodulator robust to phase noise of cable STB tuners

The 1024-QAM demodulator we developed for cable television networks uses a modified symbol-decision region to reduce the effects of phase noise due to set-top-box tuners. The symbol-decision region is optimized by analysis of phase noise distribution. Simulation results show that good demodulation characteristics of a 1024-QAM signal are achieved under typical phase-noise conditions. The results are verified in a field trial with a prototype demodulator and an off-the-shelf tuner.