研究了基于脉冲编码调制的布里渊光时域分析(BOTDA)系统原理,该系统向传感光纤注入经脉冲编码调制后的光脉冲序列,在接收端用数据处理程序恢复系统的单脉冲响应,从而提高BOTDA系统的信噪比、温度和应变分辨率。理论研究了BOTDA系统中Simplex码、Golay码和CCPONS码的编码和解码原理;利用Matlab仿真研究了不同脉冲编码调制的BOTDA系统的时域输出信号,并对比分析了三种编码对系统信噪比的改善情况,结果表明采用脉冲编码技术可使BOTDA系统性能得到有效提升,CCPONS码调制时可获得最佳系统性能,Simplex码次之。 The principle of Brillouin Optical Time Domain Analysis (BOTDA) system based on pulse code modulation is studied. The system injects the optical pulse sequence modulated by pulse code into the sensing fiber, and restores the single impulse response of the system by the data processing program at the receiving end , Thereby improving the signal to noise ratio, temperature and strain resolution of the BOTDA system. The theory of encoding and decoding Simplex code, Golay code and CCPONS code in BOTDA system is studied in theory. The time-domain output signal of BOTDA system modulated by different pulse code is studied by Matlab simulation. The results show that the performance of BOTDA system can be improved effectively by using pulse code technology, and the best system performance can be obtained when modulating CCPONS code, followed by Simplex code.