数字查表法合成周期信号是一种最常用的直接数字频率合成技术。该方法若再利用小数地址序列生成技术 ,可达到很高的频率分辨率。然而 ,采用小数地址序列生成技术合成波形 ,会产生“寄生谐波”。作者采用非均匀采样周期信号谱分析方法 ,研究以查表法合成的周期信号的频谱 ,推导了合成周期信号的信噪比 ,并揭示了其一些重要的性质。这些理论 ,对于设计满足一定信噪比要求的数字波形合成器及对其性能的分析具有指导意义 Digital look-up table synthesis cycle signal is one of the most commonly used direct digital frequency synthesis technology. If this method uses fractional address sequence generation technology, high frequency resolution can be achieved. However, using fractional address-generation techniques to synthesize waveforms results in “parasitic harmonics.” The author uses non-uniform sampling period signal spectrum analysis method to study the spectrum of the periodic signal synthesized by look-up table, deduces the signal-to-noise ratio of the synthesized period signal and reveals some important properties. These theories are instructive in designing a digital waveform synthesizer that meets a certain signal-to-noise ratio requirement and in analyzing its performance