A stability algorithm for high-level QAM carrier recovery

This paper proposes a structure of the joint frequency-phase carrier recovery loop for all-digital Quadrature Amplitude Modulation (QAM)receivers. The steady-state estimation variance is greatly reduced by introducing a non-zero-mean input to the Stop-and-Go controller. It has been verified by simulation tools that the circuit can acquire frequency offset up to 6% of the symbol rate and phase offset up to 30 degree in only 11000 symbol periods, while its steady-state phase jitter also significantly reduces to 0.11 degrees.