摘要： 针对定时同步算法捕获时间长、稳定性差和误码率高等问题，提出一种改进的Gardner定时同步算法。分析不同插值滤波器对定时同步的影响，并选用分段抛物线插值滤波器。对QPSK调制信号进行开环和闭环分析。仿真结果表明，与现有算法相比，改进的定时同步算法捕获时间缩短0.005 s，进入同步后的均方误差减小，当信噪比大于8 dB时，误码率明显降低。
关键词:
定时同步,
插值滤波器,
定时误差检测器,
S-曲线,
Gardner算法,
QPSK调制
Abstract: Aiming at the problem that the existing timing synchronization algorithm needs a long time acquisition, poor stability and high error rate, an improved Gardner synchronization algorithm is proposed. On the analysis of different interpolation filter, piecewise parabolic interpolation filter is used in synchronization structure. For QPSK signal, open-loop and closed-loop analysis is carried out respectively. Simulation result shows that compared with previous algorithms, the proposed synchronization method has 0.005 s shorter acquisition and then the mean square error is reduced. Moreover, the bit error rate is significantly reduced while signal to noise ratio is greater than 8 dB.
Key words:
timing synchronization,
interpolation filter,
timing-error detector,
S-curve,
Gardner algorithm,
QPSK modulation
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