软件无线电直接射频采样的高速ADC系统研究

Direct RF sampling ADC system on software radio

针对混合滤波器组ADC系统因其ADC模拟输入带宽低而不能对频率较高的射频模拟信号直接进行模 /数转换的瓶颈 ,本文提出了一种基于Nyquist采样定理和带通采样定理的抽取器数学模型 ,对该数学模型进行时域、频域的分析证明后 ,设计了一种基于该数学模型的SHA抽取器 ,进而在混合滤波器组ADC系统的基础上 ,提出了高速混合滤波器组ADC系统。它能将带宽为 (2MHz～ 2 0 0 0MHz)的射频模拟信号直接模 /数转换 ,且分辨率达到 12比特以上 。

The bottleneck of hybrid filter banks ADC system is that it cannot sample directly higher radio frequency signal because of lower analog input bandwidth of its ADC. In order to remove it, a kind of downsampler model based on Nyquist and bandpass sampling theorem is presented, analyzed and proved in time and frequency domain, in addition a downsampler is designed according to the model. On the basis of hybrid filter banks ADC system, a class of high speed hybrid filter bank ADC system is proposed. It can convert RF analog signal (2MHz～2000MHz) into digital signal with 12 bit-resolution, and satisfy requirements of direct RF sampling on software radio.