数字波合成技术改进方案的理论分析

Theoretical Analysis of an Advanced Scheme for Digital Synthesis Technique

移相细度和失真度是评价数字合成正弦波质量的两项重要指标。利用傅立叶级数，本文分析了数字合成正弦波的移相细度与离散点数、转换点数的数学关系。同时，本文还分析了Ｄ／Ａ转换器字长对移相细度的影响。据此理论，文中提出了一种数字合成正弦波的新方案。

Phase shift resolution and total harmonic distortion (THD) are two important parameters used to evaluate the equality of sine waveform generated by digital synthesis. An analysis is presented, by use of the Fourlier Series, of the mathematical relations of THD with the total number of converting points in a cycle of sine function, phase shift resolution and the number of sampling points. It also discusses the influence of the word legnth of the D/A converter on phase shift resolution. Based on these analyses, a new scheme of digital synthesis is proposed.