群时延失真对天线组阵合成信噪比的影响分析

为量化分析天线信道间群时延失真分布的差异性对天线组阵合成信噪比的影响，首先建立了天线组阵信道群时延失真分布特性的数学模型，并基于该数学模型，利用分数时延全通滤波器对群时延全通滤波器进行补偿，从而建立了能够准确模拟数学模型群时延分布特性的仿真模型，而后通过理论分析得到了点频和宽带两种信号形式的合成信噪比损失计算公式，最后仿真验证了理论分析的正确性。研究结果表明，天线数越多、带宽越宽、群时延分布差异性越大，合成信噪比损失越大，对于天线数为100，带宽为1GHz的大规模宽带天线组阵，当频带边缘群时延的标准差大于4 ns时，合成信噪比损失大于0.5 dB。 

Analysis of Influence of Group Delay Distortion on Combining SNR of Antenna Arraying

The influence of the distributing difference of group delay distortion between channels of antenna arraying on the SNR of the combining signal is analyzed quantificationally. Firstly, the mathematic model of group delay distortion of the antenna arraying channel is established, and based on the mathematic model, a simulate model is established by using the fractional delay all-pass filter to compensate the group delay all-pass filter, and it enables the simulate model to simulate the characteristic of group delay distortion of the mathematic model accurately. Secondly, two theoretical formulas of the combining loss for single frequency signal and wideband signal are theoretically derived. Finally, the correctness of the theoretical analysis is verified by simulation experiments. Research shows that the more the antenna number, the wider the bandwidth and the larger the difference of group delay distribution, the greater the combining loss is. As for a large-scale and broadband antenna arraying which has 100 antennas and a bandwidth of 1 GHz, when the standard deviation of maximum group delay distortion of the band edge is greater than 4 ns, the combining loss will be greater than 0.5 dB.