中文摘要：

基于用二阶多项式表示的基本谱密度函数,提出直扩码分多址（DS-CDMA）系统中一类带限码片波形——二阶连续脉冲.通过这类脉冲,对于给定的滚降系数,可以找到衰减速度、眼图开启度、包络均匀性和抗多址干扰能力等性能均优于频域平方根升余弦Nyquist脉冲的波形.从“归一化带宽—脉冲形状因子”乘积、时间波形衰减速度、眼图开启度、包络均匀性等角度,详细分析了二阶连续脉冲,为CDMA系统中码片波形的选择提供了基本依据.

英文摘要：

Based on the elementary density function of a second order polynomial, a class of second order continuity chip pulses in direct sequence code division multiple access （DS-CDMA） systems was proposed. From this class of pulses, some members can be found having faster decaying rate, bigger eye opening, more uniform envelope and stronger anti-multiple-access-interference capability than frequency domain square-root raised cosine Nyquist waveform. The normalized-bandwidth-pulse-shape-factor product, the decaying rate of the tail of time waveform, the opening of the eye diagram, and the envelope uniformity of the second order continuity pulses were addressed, which provides the basic information for the selection of the chip pulse for CDMA systems.