基于FPGA的DSTFT算法对FSK信号解调的改进
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摘要
针对运用离散短时傅里叶变换(DSTFT)算法实现解调2FSK信号时其存在的码元同步的问题。提出通过运用载波的功率谱估计和码元偏移的采样点数的关系,在系统通信开始的时候先实现精确的码元同步状态。由于在无线传输过程中存在噪声和频飘等现象,需要运用载波的功率谱估计跟踪码元同步状态,并且记录码元偏移的采样点数。当解调过程中再出现不同步状态的时候可以快速、精确的实现码元再次同步。并且通过仿真和在FPGA实现上表明该同步算法比其他同步算法误码率更低,并且在EM-WMD接收机上得到了应用。
For using discrete short-time Fourier transform(DSTFT) algorithm to realize the demodulation 2FSK signal when the symbol synchronization problem of its existence.Put forward by the application of carrier wave power spectrum estimation and element migration of the relationship between the sampling points at the beginning of the system communication to realize accurate symbol synchronization state.Because in the process of wireless transmission phenomenon such as noise and frequency drift, need to use the carrier power spectrum estimation tracking symbol synchronization state, and record the element migration of sampling points.When demodulation can appear out of sync status again in the process of the realization of the fast and accurate symbol synchronization again.And through the simulation and shows that the synchronization algorithm on the FPGA implementation error rate is lower than other synchronization algorithm, and its application on the receiver EM-WMD.
For using discrete short-time Fourier transform(DSTFT) algorithm to realize the demodulation 2FSK signal when the symbol synchronization problem of its existence.Put forward by the application of carrier wave power spectrum estimation and element migration of the relationship between the sampling points at the beginning of the system communication to realize accurate symbol synchronization state.Because in the process of wireless transmission phenomenon such as noise and frequency drift, need to use the carrier power spectrum estimation tracking symbol synchronization state, and record the element migration of sampling points.When demodulation can appear out of sync status again in the process of the realization of the fast and accurate symbol synchronization again.And through the simulation and shows that the synchronization algorithm on the FPGA implementation error rate is lower than other synchronization algorithm, and its application on the receiver EM-WMD.
引文
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[4]殷晓中,于盛林.信号的时频分析理论与应用评述[J].现代电子技术,2006,29(21):118-120.
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[6]王楠,古瑞江,于红毅.一种新型的FSK解调系统设计[J],通信技术,2008,41(9):29-321.
[7]金文光,张正宇,唐少华.2FSK信号DSTFT解调算法中的同步新方法[J].浙江大学学报,2011,45(6):1027-1031.
[8]宋鹏,田乐.基于FPGA的时间同步精度的设计与实现[J].西安工程大学学报,2014(1):89-93.
[2]胡延平,李纲,王展,等.一种基于DSTFT解调2FSK信号的新方法[J].通信学报,2000,21(6):54-59.
[3]冯小平,李红娟.用离散STFT实现FSK调制信号的数字解调方法[J].西安电子科技大学学报,2001,28(6):812-815.
[4]殷晓中,于盛林.信号的时频分析理论与应用评述[J].现代电子技术,2006,29(21):118-120.
[5]约翰逊,等.软件无线电[M].北京:机械工业出版社,2008:21-27.
[6]王楠,古瑞江,于红毅.一种新型的FSK解调系统设计[J],通信技术,2008,41(9):29-321.
[7]金文光,张正宇,唐少华.2FSK信号DSTFT解调算法中的同步新方法[J].浙江大学学报,2011,45(6):1027-1031.
[8]宋鹏,田乐.基于FPGA的时间同步精度的设计与实现[J].西安工程大学学报,2014(1):89-93.