基于Delta-Sigma技术的直接数字频率发生器的设计  

An Direct Digital Frequency Synthesizer Base on Delta-Sigma Noise Shaping

作　　者：李志恒[1] 

机构地区：[1]电子科技大学电子工程学院,四川成都611731

出　　处：《电子质量》2012年第9期17-18,27,共3页Electronics Quality

摘　　要：直接数字频率合成技术(DDFS)具有很好的频率渐变与很高的频率分辨率,然而该技术却伴随着严重的谐波噪声,主要的谐波噪声是相位截断噪声。该文将介绍一种新型的DDFS结构,该结构采用了Delta-Sigma噪声整形技术,有效地减少由相位截断引入的噪声。经测试,信号的信噪比可以大于60dB,同时减小了硬件的复杂性。A direct digital frequency synthesizer（DDFS） exhibits agile frequency switching and fine tuning resolution.However,it suffers from severe spurious harmonic noise.There are two main spurs：phase truncation error and DAC quantization noise.This paper presents a new DDFS architecture employing a Delta-Sigma noise shaping to reduce the spurs caused by the phase truncation and using a 1-bit DAC based on the Delta-Sigma modulator to reduce the quantization noise.The measured signal noise ratio （SNR） is greater than 60dB and reduce the complexity of hardware.

关 键 词：直接数字波形产生 DELTA-SIGMA FPGA 

分 类 号：TN741[电子电信—电路与系统]