摘要
针对深空探测中常规点数的FFT无法对极微弱信号进行精确的频率引导,而超长点数的FFT无法用现有器件实现,提出一种基于数字信道化的并行FFT频率引导方法。接收信号先经过数字信道化处理,均匀划分为若干窄带信号,然后分别对各子带信号进行FFT运算,最后通过对各子带有效谱线的联合检测完成载波频率的精确估计。在等效219点FFT的频率引导模块FPGA实现中,通过FFT模块的复用节约了硬件资源开销。测试结果表明:在8MHz采样率下该模块的测频精度小于10Hz。
In deep space exploration, normal points FFT cannot exaetly fulfill the frequency guide for very weak signals while very large size FFT cannot be computed by COTS. A parallel FFT method based on digital channelization is proposed to fulfill the frequency guide. The input signal is first divided into several narrow bands and FFT is computed in every sub-band. Then frequency estimation is performed by jointly detecting the valid sub-band spectrum lines. In FPGA implementation of the module equivalent to 29 points FFT, the FFT module is reused for resource saving. The test results show that the resolution is less than 10Hz when the sampling rate is 8MHz.
出处
《国防科技大学学报》
EI
CAS
CSCD
北大核心
2009年第3期43-47,共5页
Journal of National University of Defense Technology
基金
国家部委预研基金资助项目(113030401)
关键词
深空探测
极微弱信号
高精度测频
数字信道化
deep-space explaration
very weak signal
high resoluton frequency estimation
digital channelzation
