基于后置带通滤波的中频信号A/D变换精度提高方法

Method of Improving Resolution of A/D Conversion in Intermediate-Frequency Signals Based on Post Bandpass Filtering

用低位A/D变换器通过滤除量化噪声达到高位A/D变换器的性能,一直是信号处理研究人员关注的问题。针对通信中常见的中频带通信号,本文提出了一种采用后置数字带通滤波器降低信号量化噪声、改善A/D变换精度的方法,以一种常见的中频带通信号为例,分析了该方法的性能,并通过仿真进行验证。结果表明,对A/D变换后的信号进行后置数字带通滤波处理,量化噪声大幅度降低,A/D变换性能得以明显提高。本文还对量化噪声的传统统计模型进行了改进,放宽了传统统计模型中量化噪声为白噪声的假设条件。

How to achieve high-resolution ADCs from low-resolution ones by filtering quantization noise is the key problem of signal processing researchers. Considering IF bandpass signals in communication, a method is proposed to reduce the quantization noise and improve the resolution of A/D conversion by adding a post-bandpass filter. Then the method is analyzed and tested by numerical simulations with a common IF bandpass signal as an example. Results show that the quantization noise is observably re- duced,through bandpass filtering for quantized signals. Therefore, the A/D conversion performance are improved obviously. In addition, in the aspect of theory, this paper revises certain traditional views on the statistic model of quantization noise and loosens the assumption condition that the quantization noise is a white one.