College of Electronic Science, National University of Defense Technology, Changsha 410073, China.
Sensors (Basel). 2018 Jun 1;18(6):1768. doi: 10.3390/s18061768.
The Nyquist Folding Receiver (NYFR) is a novel ultra-wideband (UWB) receiver structure that can realize wideband signal monitoring with fewer components. The NYFR induces a Nyquist zone (NZ)-dependent sinusoidal frequency modulation (SFM) by a modulated local oscillator (LOS), and the intercepted linear frequency modulated (LFM) synthetic aperture radar (SAR) signal will be converted into an LFM/SFM hybrid modulated signal. In this paper, a parameter estimation algorithm is proposed for the complicated NYFR output signal. According to the NYFR prior information, a chirp singular value ratio (CSVR) spectrum method based on singular value decomposition (SVD) is proposed to estimate the chirp rate directly before estimating the NZ index. Then, a fast search algorithm based on golden section method for the CSVR spectrum is analyzed, which can obviously reduce the computational complexity. The simulation shows that the presented algorithm can accurately estimate the parameters of the LFM/SFM hybrid modulated output signal by the NYFR.
奈奎斯特折叠接收机（NYFR）是一种新颖的超宽带（UWB）接收机结构，它可以用更少的组件实现宽带信号监测。NYFR 通过调制本振（LOS）产生与奈奎斯特区（NZ）相关的正弦调频（SFM），截获的线性调频（LFM）合成孔径雷达（SAR）信号将被转换为 LFM/SFM 混合调制信号。本文针对复杂的 NYFR 输出信号提出了一种参数估计算法。根据 NYFR 的先验信息，提出了一种基于奇异值分解（SVD）的 Chirp 奇异值比（CSVR）谱方法，该方法可以在估计 NZ 指数之前直接估计线性调频斜率。然后，分析了基于黄金分割法的 CSVR 谱的快速搜索算法，该算法可以明显降低计算复杂度。仿真结果表明，所提出的算法可以通过 NYFR 对 LFM/SFM 混合调制输出信号的参数进行准确估计。
