基于Mathematica程序,我们提出了一种对分段连续周期性阶梯信号进行频谱分析的方法,该方法对包含多个有限间断点的分段连续信号的频谱分析具有普遍意义.用此方法对数模转换器合成的阶梯三角波的频谱进行了分析,给出了能够完成频谱分析,作出波形图和对应频谱图的Mathematica程序.本研究表明:阶梯三角波的频谱结构由三角波每个周期中的阶梯数2k决定. Based on the Mathematica program, we propose a method for spectrum analysis of stepped continuous periodic signal, which is of universal significance for the spectrum analysis of the continuous signal with several finite discontinuous points. Using this method, The spectrum of ladder triangle wave synthesized by the converter is analyzed, and the Mathematica program which can finish the spectrum analysis, make the waveform diagram and the corresponding spectrogram is given.This study shows that the spectral structure of the ladder triangle wave is composed of steps 2k Decided.