基于低通等效的非正弦时域正交调制系统研究

Research on non-sinusoidal orthogonal modulation in time domain based on low-pass equivalent

针对基于椭圆球面波函数(Prolate Spheroidal Wave Function,PSWF)的非正弦时域正交调制系统在应用中遇到的带通PSWF信号实时产生困难、系统对同步误差敏感及实现复杂度高的问题,从带通信号低通等效的基本原理出发,分析了带通PSWF脉冲信号的低通等效形式,论证了正交带通PSWF脉冲信号的低通等效正交条件,提出了基于低通等效的相关接收方法,并对其性能和抗同步误差能力进行了分析.理论分析和仿真结果表明,非理想同步条件下,基于低通等效的解调方法具有更好的对抗同步误差的能力,对比于优化的解调方法,系统性能仍有至少2dB的提高,这种方法还可降低系统的实现复杂度.

It is difficult to generate a bandpass prolate spheroidal wave function(PSWF)pulse signal in real-time,and the non-sinusoidal orthogonal modulation in time domain based on PSWF is sensitive to the synchronization timing error and hard to realize.For these issues,from the low-pass equivalent principle of bandpass signal,the low-pass equivalent form of the bandpass PSWF pulse signal is analyzed,and the equivalent orthogonal condition of the complex envelopes of two bandpass PSWF signals isderived,then,a demodulate method based on low-pass equivalent principle is proposed.The bit error rate(BER)performance is analyzed when the system is ideal or non-ideal synchronized.The mathematical deduction and simulation results both show that the demodulate method proposed is better when system is unideally synchronized.Compared with other demodulate methods,the method proposed at least improved the BER performance by 2dB,and the complexity of the system can be greatly reduced.