基于FPGA的DDS杂散分析及抑制方法

摘要

首先介绍了采用直接数字频率合成（DDS）技术的正弦信号发生器的基本原理和采用FPGA实现DDS信号发生器的基本方法．然后结合DDS的原理分析了采用DDS方法实现的正弦信号发生器的优缺点，其中重点分析了幅度量化杂散产生的误差及其原因，最后针对DDS原理上存在的幅度量化杂散，利用FPGA时钟频率可调的特点，重点提出了基于FPGA实现的DDS正弦信号发生器的两种改进方法，经过MATLAB仿真验证，改进方法较好的抑制了幅度量化杂散．减小了误差。%This paper introduces the basic principles of the sinusoidal signal generator using direct digital frequency synthesis (DDS) technology and the basic achieve methods which use FPGA,then analyse the advantages and disadvantages of DDS sinusoidal signal generator combined the principles of DDS,among it I focus on Amplitude quantization spurious and the reason which produce error, Finally, against amplitude quantization spurious of principle , I focus on two improved methods of the DDS sinusoidal signal generator based on FPGA which has the characteristic of frequency adjustable,we can draw a conclusion through matlab simulation that the improved methods have a good effect to restrain Amplitude quantization spurious and reduced the error.