软件化雷达的多路超高速ADC数字谱分析

用于软件雷达硬件平台的并行多路等效时间超高速ADC系统中,客观地存在着诸多不可避免的工作非均匀性,如:时基抖动、通道直流偏置不均衡及通道增益不一致等等,而造成取样输出信号的频谱发生畸变,影响雷达系统性能.综合讨论了由于采样非均匀和通道偏置及增益不一致对取样信号数字谱的影响,在矩形抽样和理想抽样情况下,建立了该信号数字频谱的完整数学模型,并以理想抽样的正弦信号为例进行详细分析,得到了采样系统输出信噪比的计算公式,为系统的后续补偿校正,及对软件雷达系统指标的确定与分配提供了参考和依据.

Evaluation of a Ultra-high Speed Non-uniformly Working ADC with Parallel Structure in the Software Radar

In the ultra-high speed sampled ADC system with time-interleaved structure of the software radar,the input signal is sampled non-uniformly because of the sampling-time offset and gain difference of ADC,which product the distortion of the signals digital spectrum.In this paper,we have synthetically researched the digital spectra of the signal sampled non-uniformly by this ADC with sampling-time offset and gain difference,And derived its digital spectrum representation,Furthermore,a detailed spectrum analysis of the non-uniformly sampled sinusoid is presented to obtain the signal-to-noise ratio.At last the results of computer simulation that verify the correction of the theory are given.The result provides the useful reference to select the indexes of the software radar system using the ADC with Parallel Structure.