对线性载波调制信号采样的研究

Research of Sampling of Linear Carrier Modulation Signal

分析了线性载波调制信号经欠采样后,满足一定的条件时可以恢复基带信号波形。给出了达到这种频谱重叠条件的采样率的下限即采样率等于2倍的基带信号带宽以及何时能取到这一下限。同时提出对数字载波调制系统的采样不需要重建波形而只要恢复码元序列的思想。应用修正的Gardner算法可部分地解决采样时钟偏差对信号恢复的影响。

when a certain condition is satisfied, a linear modulation signal after sub-sampling can be reconstructed. The lower limit which fits the certain condition has been given. Namely the sampling rates equals to twice the baseband signal bandwidth. And the paper also gives the condition to attain this lower limit. At the same time, it proposes that the sampling based on digital modulation signal does not need to reconstruct the waveform, but to recover the code. And the application of modified Gardner algorithm may partly eliminate the influence of sampling clock deviation on signal restoration.