摘要:在分析了直接数字式信号合成系统中波形存储器输出序列的离散傅里叶变换(DFT)与合成信号的频谱之间关系的基础上,给出几种基于原输出序列设计的波形序列,推导出关于它们DFT的几个重要结论,并用MATLAB程序对结论进行了验证。根据结论,在利用波形存储器中限定数据进行信号合成时,通过波形设计可提高合成信号的频率分辨率或按一定规律调整合成信号的频谱。
关键词: 直接数字式信号合成 波形设计 DFT 频率分辨率
分类号: TN911.3
Waveform Design and Spectral Analysis in Direct Digital Signal Synthesizing
Tian Xinguang Li Lin Zhang Eryang
( School of Electronic Science and Engineering , NUDT, Changsha 410073 )
Abstract: In this paper, the relationship between the DFT of an output sequence of the waveform memory in a direct digital signal synthesizing system and the frequency spectrum of the correspo-nding synthesized signal is analyzed. Then, several designed waveform sequences based on the output sequence are presented , and several important conclusions about their DFT are respective-ly derived and confirmed with MATLAB programs.It is shown that the waveform design proposed is an effective method to synthesize signals of high frequency resolution or of variable spectrum with definite data in the waveform memory.
Key words: direct digital signal synthesizing waveform design DFT frequency resolution