正弦信号源波形失真的一种精确评价方法

A Precise Evaluation Method for the Distortion of Sinusoidal Sources

叙述了正弦信号源失真的分类 :谐波失真、噪声失真和杂波失真 ;讨论了失真测量的基本技术 (模拟法和FFT法 )的优点和局限性 ,分析了失真测量技术的难点和技术状况 ;介绍了谐波失真和总失真度的定义。提出了使用正弦波曲线拟合法评价正弦波信号源总失真度的过程 ,在能量守衡以及失真和信号本身不相关的前提下 ,详细分析和推导了量化误差对失真度评价的影响及修正公式 ,实现了正弦波信号源总失真度的精确评价 ,实验结果验证了该方法的正确性及切实可行性。同时 ,对评价方法进行了误差分析 。

The distortions of sinusoidal sources can be classfied into the harmonic, noise and spurious distortion. The analogue method and FFT method, as the basic measurement techniques for distortion are discussed, the technique and the difficulties of distortion measurement is analyzed in detail. The definitions of both harmonic distortion and total distortion are introduced. By using sine wave curve fit, a course of total distortoin measurement method of sinusoidal sources is presented. In the premises of both the energy always keeping constancy and the distortion always being independent of the signals, the influence of quantization error in the distortion measurement is developed, and then, the corrected formula of distortion measurement is presented. Finally, the precise measurement of distortion is achieved. Both the validity and feasibility are validated. Meanwhile, the error analysis of total distortion is given. The method above can applied to both the precise evaluation of total distortion and the distortion calibration of sinusoidal sources.