In this paper, we first introduce the development of QAM demodulator and the basic principle of QAM(Quadrature Amplitude Modulation). Emphases is on the timing recovery technique to recover the symbol timing using a fixed clock that is not synchronized to the transmitter clock and non-ideal interpolation in the QAM demodulator. On the basis of Matlab simulation, this paper proposes a family of traditional and optimized polynomial interpolators. And a statistical analysis of timing error detector is presented. In the end, FPGA circuit is designed in Quartus. |