小数分频频率合成器的Σ-△调制分析及优化  

Σ-△ modulation analysis & optimization in fractional-N frequency synthesizer

作　　者：杨建明 

机构地区：[1]广东中星电子有限公司,广东珠海519000

出　　处：《电子技术应用》2018年第3期19-21,30,共4页Application of Electronic Technique

摘　　要：分析Σ-△量化对小数分频频率合成器相位噪声及杂散的影响,优化Σ-△量化器,提升频率合成器性能。分别分析了Σ-△量化器阶数、频率合成器带宽、Σ-△量化器工作频率及Σ-△量化器位数对频率合成器的影响,并建立数学模型。使用MATLAB验证了数学模型,提出输入信号预先插入零点,迭加低能量白噪声的二阶Σ-△量化器适合于Σ-△频率合成器,且通过提高Σ-△量化器工作频率而提升Σ-△频率合成器带宽。Analyzed the impaction of Σ-△ modulation on Σ-△ frequency synthesizer ′ s phase noise and spurs, and optimized Σ-△modulator to improve the performance of Σ-△ frequency synthesizer. The Σ-△ modulator ′ s order, working frequency, quantization bits, and the bandwidth of frequency synthesizer were analyzed, and builded up mathematical model which were verified by MATLAB. The results showed that 2 nd order Σ-△ modulator ＇ s with pre-emphasized zeros and injecting low level white noise can work well for Σ-△ frequency synthesizer. At the same time, high bandwidth Σ-△ frequency synthesizer can be obtained by rising Σ-△modulator ′ s working frequency.

关 键 词：相位噪声 杂散 Σ-△ 

分 类 号：TN432[电子电信—微电子学与固体电子学]