Design of a QAM receiver with the Kalman algorithm for adaptive carrier synchronization

A quadrature amplitude modulation (QAM) receiver by exploiting a two-state Kalman filter algorithm for carrier recovery is designed and verified on Xilinx Spartan-3 FPGA. The major advantage of the Kalman-based scheme over the conventional phase-locked loop (PLL) is the self-adaptation of loop bandwidth for better compromising the tradeoff between fast acquisition and small steady-state variation of phase tracking. From simulation and implementation results, it is shown that the Kalman-based approach can achieve much shorter acquisition time than the conventional PLL with similar steady-state phase tracking performance.