研究了将光电振荡器产生的混沌信号作为物理随机数熵源时的采样率上限，通过研究不同的采样率对混沌熵源的随机特征的影响，得到满足随机采样条件的最大采样率；信号的随机特征通过自相关函数和功率谱表征，通过游程检验以及正态性检验得到最大采样率。仿真结果表明，对混沌信号进行随机采样时，存在一个采样率上限；在此基础上，通过计算可得到最大随机采样率和最大正态采样率，并分别研究了这两种最大采样率随光电振荡系统反馈强度的变化。

In this paper， the upper limit of sampling rate of chaotic signals which are generated by an optoelectronic oscillator and used as the entropy source of physical random number is studied. The effects of different sampling rates on the random characteristics of the chaotic entropy source are analyzed. The maximum sampling rate for random sampling is obtained. The random characteristics of the signal are characterized by the autocorrelation function and power spectra. The maximum sampling rate is numerically studied by the run test and normality test. Simulation results show that， for the random sampling of chaotic signals， there exists an upper limit of sampling rate. On this basis， the maximum random sampling rate and the maximum normal sampling rate are obtained by calculations. The changes of these two maximum sampling rates with the feedback intensity of the optoelectronic oscillation system are numerically studied.