【作者】 朱国军；

【导师】 张浩；

【作者基本信息】 西安电子科技大学 ， 信号与信息处理， 2007， 硕士

【摘要】 在现代雷达系统设计中,数字零中频接收正逐渐成为重要的组成部分。中频采样数字化接收很好的克服了传统正交采样接收幅相不平衡的缺点,对雷达多普勒镜像频率的抑制达到了令人满意的结果。本论文对直接中频采样及数字相干检波进行了研究,首先介绍了传统接收机原理以及其存在的问题,分析了幅相误差与镜频抑制比的关系。然后介绍了采样理论和多速率信号处理的基本概念和基本理论。接着对三种正交相干检波方法的原理,具体结构进行了研究,通过计算机仿真,分析了三种方法的性能,同时本文也给出了正交相干检波的工程实现,包括各部分设计的原理框图以及仿真时序。最后从实际应用的角度出发,对A/D转换器位数、滤波器系数位数等多种影响镜频抑制的因素进行了分析。更多还原

【Abstract】 In modern radar system, digitized directly IF receiver plays a more important role. IF digital receiver eliminates the residual at the image frequency resulting from the amplitude and phase unbalance between I/Q channels in conventional approach to coherent detection. This dissertation researches the theories of directly IF sample and digital quadrature coherent detection. Firstly, the dissertation introduces the problem of the conventional receivers, and analyses the relation between the error of amplitude and phase and mirror frequency. Second, the dissertation gives the principle of sampling theory and multi-velocity signal processing. Then,it researches the principles and structures of three quadrature coherent detection methods. The simulating results obtain their different suppressing performance of mirror frequency. The dissertation presents the realization of quadrature coherent detector and gives the circuit block and the simulation. Lastly, this dissertation analyses the effect to the mirror frequency of the number of bits of A/D convertor and the filter. It is a good reference for practical using.更多还原