基于HSP50016的数字下变频处理

Digital down Conversion Processing Based on HSP50016

在数字信号处理中,通常需要将中频信号下变频成两路正交的I、Q基带信号,然后再作进一步的处理。而I、Q通道间的增益误差和相位误差会造成镜像干扰,影响系统性能。采用模拟方式解决镜像干扰,使得系统设计非常复杂,而且性能不佳。分析了I、Q通道的增益误差和正交误差对镜像干扰抑制比的影响,在系统中采用DDC芯片作下变频处理。实验结果证明,这种方法可以有效抑制镜像干扰。

In digital signal processing,it is necessary to convert intermediate frequency signals to baseband signals before the further processing. But any gain error or phase error between in-phase (I)path and quadrature phase (Q)path in the system will cause hermitian image interference and degrade the performance of the system. The analog methods will make system more complex. The effect of the gain and phase errors on Hermitian image rejection is investigated. The DDC chip is adopted in the system to convert IF signals to baseband signals. The experimental results illustrate that this method is effective in Hermitian image rejection.