基于FRFT的SNCK信号非相干解调  

SNCK signals incoherent demodulation based on FRFT

作　　者：孙志国[1] 周彬[1] 田丹阳 郭黎利[1] 熊磊[2] 

机构地区：[1]哈尔滨工程大学信息与通信工程学院,黑龙江哈尔滨150001 [2]北京交通大学轨道交通控制与安全国家重点实验室,北京100044

出　　处：《系统工程与电子技术》2013年第12期2600-2606,共7页Systems Engineering and Electronics

基　　金：国家自然科学基金(61101141);中央高校基本科研业务费专项资金(HEUCF130819);轨道交通控制与安全国家重点实验室开放基金(RCS2011K009)资助课题

摘　　要：在采用相干解调方法进行接收时,正弦型非线性切普键控(sine non-linear chirp keying,SNCK)信号受相位误差和多普勒频移影响较大,针对此问题提出一种将其近似为分段线性调频(linear frequency modulation,LFM)信号,采用分数阶傅里叶变换(fractional fourier transform,FRFT)进行解调的非相干解调方法。将FRFT解调方法与经典相干解调方法进行对比,通过理论推导和仿真分析发现,在严格同步条件下,SNCK信号相干解调性能优于FRFT解调方法,并且信号码元长度对FRFT解调性能有微弱的影响。但FRFT解调不受相位误差的影响,且具有相对较高的抗多普勒频移能力。The sine non linear chirp keying （SNCK） signal is affected by the phase error and Doppler fre quency shift when received by the coherent demodulation method. To solve this problem, by using the segment linear frequency modulation （LFM） signal to approximate it, a fractional Fourier transform （FRFT） incoherent demodulation method is proposed. The performances of FRFT demodulation and coherent demodulation are compared by theoretical analysis and simulation. Under strict synchronization conditions, the SNCK signals de-modulation performance using the coherent demodulation is better than the FRFT demodulation, and the length of the signal element has slight effect on the FRFT demodulation performance. However, the FRFT demodula tion is not affected by the phase error, and has a high ability to resist the Doppler frequency shift.

关 键 词：解调 非相干解调 分数阶傅里叶变换 正弦型非线性切普键控 相位误差 

分 类 号：TN911[电子电信—通信与信息系统]