基于迭代插值的实复转换频率估计算法

Real-to-complex-transformation frequency estimation algorithm based on iterative interpolation

为消除实信号中负频率成分对频率估计的影响,提出一种基于迭代插值的实复转换频率估计算法。通过预估计采样信号频率,构造参考信号,并通过90°相移得到采样信号的正交分量;将采样信号与其正交分量合成为复信号实现实复转换,抑制负频率成分的影响;利用迭代插值算法估计复信号的频率,重新构造参考信号并生成正交分量与复信号,并对复信号进行频率估计,得到精确的频率值。仿真实验表明:所提算法消除了负频率成分的影响,改善了抗噪性,提高了估计精度,使得频率估计的均方误差更接近于克拉美罗下限。此外,在LFMCW雷达上进行了实测实验,验证了所提算法的有效性。

To eliminate the influence of negative frequency component of a real sinusoid signal on the frequency estimation,a real-to-complex-transformation frequency estimation algorithm based on iterative interpolation was proposed.The sampled signal frequency was pre-estimated,the reference signal was constructed and the orthogonal component of the sampled signal was obtained through 90 degree phase shift.Then,the sampled signal and its orthogonal component were synthesized into a complex signal to realize the real-to-complex-transformation,and the influence of the negative frequency component was thus suppressed.On this basis the complex signal frequency was estimated by using an iterative interpolation algorithm,the reference signal and orthogonal component and complex signal were rebuilt,and the exact frequency value was identified by estimating the frequency of the complex signal.The results of simulation experiments indicate that the proposed algorithm eliminates the influence of negative frequency components,improves the anti-interference property and estimation accuracy.The root mean square errors of the frequency estimation are closer to the Cramer-Rao lower bound(CRLB).Moreover,the efficacy of the proposed method was validated by measurement experiments on LFMCW radars.