用于数字频率合成器的NCO实现与优化

Numerically Controlled Oscillator Used for Digital Frequency Synthesizer: Realization and Optimization

文章分别介绍了基于查找表法和CORDIC(COordination Rotation DIgital Computer)法实现的数控振荡器的优点和缺点,并推导了CORDIC算法产生正余弦信号的实现过程。综合它们各自的优点,实现一种混合算法的数控振荡器,最后将其运用FPGA技术实现。Modelsim和quartusⅡ仿真和验证结果表明,此设计是可行的,并且易于FPGA实现。与仅仅基于查找表法实现的NCO相比,其结构更简单,精度高,耗费资源少,速度快。

The advantages and disadvantages of NCOs developed with lookup table method and CORDIC method are discussed.The realization of cosine signal with CORDIC algorithm is also derived.By synthesizing the advantages of these methods,a new NCO was designed and realized by using FPGA technology.The Modelsim and Quartus Ⅱ simulation and verification results show that this design is feasible and easy to be implemented with FPGA.Compared with NCO using only lookup table method,this one has simpler structure,more precision,less resource consumption and higher speed.