相位加扰对DDFS合成频谱的改善  

Spectral Purity Improvement of DDFS by Dither Rendering

作　　者：代向明[1] 袁国顺[1] 

机构地区：[1]中国科学院微电子研究所,北京100029

出　　处：《电子器件》2008年第2期555-557,共3页Chinese Journal of Electron Devices

摘　　要：DDFS系统中,由于波表容量的限制,带来了相位截断误差。同时,有限的数据宽度也会带来舍入误差。相位截断误差和舍入误差在频谱中的分布特点是不同的。针对相位截断误差的特点,采用相位加扰可以对合成波形质量加以改善。仿真表明,采用适当的加扰幅度后,合成波形的SFDR得到约10～20dB的改善。In DDFS system, the finite capability of waveform table lead to the phase truncation error, and the finite word length results in the rounding error. The spectral distribution characteristics due to the phase truncation and rounding are different. The spectral density caused by phase truncation can be spread out by rendering dither to the input of waveform table. The simulation shows that the broadband noise is increased, but the SFDR of synthesized wave is improved by 10-20 dB.

关 键 词：DDFS 相位截断误差 舍入误差 相位加扰 

分 类 号：TN957.51[电子电信—信号与信息处理]