【摘要】 从内积空间理论分析入手，论述了移频自动闭塞，指出当信号波形正交时在接收端能达到最佳检测．经过分析最后得出，当频偏是所选择低频信息频率的整数倍时，信号波形是正交的。这对多信息移频信息频率的选择，具有较高的参考意义。更多还原

【Abstract】 Frequency Shifting Automatic Block (FSAB) is one of the main automatic block system whick can ensure the train’s safety and improve the transport efficiency at the spot.It includes three important frequency parameters. The slection of these parameters and the relation between them is mainly be qualitative analysis. This artical bagins by theoretical analysis in inner product space. It indicated that the optimum detection is reached at the receiver when the signal waveforms is orthogonal. It concludes that the signal waveforms is orthogonal when the frequency deviation is divided with no remainder by the low information frenquency selected. This is very useful for selecting multi-information FSAB frequency in the future.更多还原