摘要
针对直接数字频率合成(DDS)技术相位截断误差引起的杂散抑制差的问题,分析有限长ROM存储空间对杂散抑制的能力,通过Matlab对正弦波表进行Nicholas线性内插结构的压缩,寻找最优的粗细波表。系统选用Nios Ⅱ为控制核心,ROM存储Nicholas结构的粗细波表,DDS控制器采用压缩波表内插还原成正弦波,实现了压缩比高、杂散低的双路DDS系统。该系统的存储压缩倍数达到128∶1,杂散抑制能力达到-88.9dB,具有相位噪声低、频谱纯度高和人机交互友好的特点。
Aiming at the problem of spurious suppression caused by the phase truncation error of the technology of direct digital frequency synthesis （DDS）, The spurious suppression ability of the finite length ROM storage space is analyzed. The optimal thickness of wave ta- ble is found using Matlab to compress the sine wave table of Nicholas linear interpolation structure. Nios II is uesd as the control core, and ROM is used to store Nicholas structure thickness of wave table,DDS controller is used to put the compression wave table in reduc- tion into a sine wave. So the high compression ratio and low stray dual DDS system is realized. The storage compression ratio of the sys- tem is 128：1 ,and the spurious suppression ability is--88.9 dB,which has the characteristics of low phase noise,high spectral purity and friendly human-computer interaction.
出处
《单片机与嵌入式系统应用》
2015年第12期27-30,共4页
Microcontrollers & Embedded Systems
