基于三线法的高动态载波同步方案

High Dynamic Carrier Synchronization Scheme Based on Three-line Method

针对在高动态下实现载波同步的问题,提出了一种基于快速傅里叶变换(FFT)三线谱法和锁相环(PLL)相结合的载波同步方案:首先在利用周期图峰值进行粗估的基础上,根据提出的新的插值公式,利用峰值左右2条谱线的幅度进行细估;再将得到的载波参数作为跟踪环路的引导频率,控制数控振荡器(NCO)的输出频率;最后通过PLL环路的自适应算法实现载波相位的动态跟踪。该方法一方面可使载波参数的实时精确估计能够适应高动态低信噪比的要求,减小了跟踪时间;另一方面在跟踪环路中由高精度的PLL进行相位补偿,二者结合可以满足动态性能和跟踪精度的要求。

In order to actualize the fast carrier synchronization algorithm based on synchronization of carrier in high dynamic, a new union Fast Fourier Transforms（FFT） and phase locked loop （PLL） is proposed. The basic idea is that firstly get a coarse estimation by using the peak of a perio- dogram and then gain an accurate estimation by using a new interpolation formula about the two spectral lines beside the peak frequency. Secondly, this paper uses the pilot frequency, to control the frequency of the sine signal produced by NCO （numerically controlled oscillator）. And finally meet the goal of carrier synchronization through the adaptive algorithm of PLL. With this method of real-time and precise estimation of carrier frequency, it can reduce the tracking time in low signal-to-noise rate and high dynamic condition. The results show that it can effectively achieve the expectations of carrier rapid acquisition and accurate tracking.