基于DFT的数字基带系统传输特性分析

Transmission Characteristics Analysis of the Digital Baseband System Based on DFT

将离散傅里叶变换(DFT)与反傅立叶变换(IDFT)变换应用到抽样序列分析中,得到适合抽样信号的DFT和IDFT关系.分析了广义基带系统对信号产生的码间串扰作用,得出抽样值无失真的广义基带系统的离散信号时域表示.根据抽样信号的DFT和IDFT关系,导出广义基带系统抽样值无失真的传输条件,并对几种基带系统进行了IDFT变换,分析了它们可能产生的码间串扰程度,讨论了基带系统的带宽与码元速率的对应关系.

The relation between DFT（Discrete Fourier Transform） and IDFT（Inverse Discrete Fourier Transform） suitable for the sampling signal can be achieved by means of applying DFT and IDFT into the analysis of the sampling sequence.The intersymbol interference effects on signals caused by baseband system in broad sense have been analyzed to show the time spectrum of the discrete signal of the baseband system in broad sense,whose sampling value is not distorted.Transmission conditions of the non-distortion sampling value of this kind of system are deducted from applying the relation between DFT and IDFT of the sampling signal.In addition,on the basis of IDFT conducted on several baseband systems the scale of the possible intersymbol interference has been analyzed and the corresponding relation between the bandwidth of the baseband system and code element rate has been discussed in the paper.