一种宽带信号数字下变频的实现方法

在宽带、超宽带应用中,单一信号带宽达几百兆赫兹;或者在不同中频同时调制多个信号产生的宽带信号也达数百兆赫兹,用常规的数字下变频方法很难实现。文章提出了一种基于DFT滤波器组的高效数字下变频结构,分析了该解调算法的特点和实现性能。对已知信号带宽和中频的宽带信号,对比了DFT滤波器组和多相分解算法的性能。对信号带宽和中频均在变化的信号,给出了实现思路。最后,给出了该DFT滤波器组的硬件实现方案。

An Implementation Approach of Broadband Signal Digital Down-Conversion

In wideband and ultra-wideband applications, bandwidth of a single signal is up to hundreds of MHz ; or multiple wideband signals generated simultaneously through modulation at different intermediate frequency （IF） is up to hundreds of MHz, therefore it is very difficult to implement by using of traditional digital down-conversion （DDC） approaches. A high efficient DDC architecture based on discrete Fourier transform （DFT） filter bank is proposed, its characteristics and implemental performance of the demodulation algorithm are analyzed. To wideband signal with known bandwidth and IF, performance comparison between the DFT filter bank and polyphase decomposition algorithm is made; and to wideband signal with varying bandwidth and IF, implementation concept is given. Finally hardware implementation scheme of the DRT filter bank is provided.