A blind 1024-QAM demodulator for cable television

A blind demodulator for 1024 quadrature amplitude modulation (QAM) is described. It uses a method that combines carrier recovery without decision-directed operation and decision feedback equalization by using a modified constant modulus algorithm (MCMA) to improve equalization. A prototype shows good 1024-QAM demodulation under multipath and frequency offset conditions. The demodulator also operates well in commercial hybrid-fiber-and-coaxial cable systems.