A Fractional-N Charge Pump (CP) PLL with a Multi-stAge noise SHaping (MASH) 1-1-1 divider controller has been reported to exhibit pairs of spurious tones called “horn spurs”. The phenomenon has been confirmed in measurements on a commercial wideband synthesizer. This brief presents an analysis of the phenomenon and techniques to mitigate it. MATLAB simulation results are presented for a type-II CP-PLL with a third order MASH Digital $\Delta \Sigma $ Modulator (DDSM) to validate the techniques that are shown. Measurement results are also presented.

中文翻译：

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减轻基于 MASH 的分数 N CP-PLL 中的“喇叭毛刺”

据报道，具有多级噪声整形 (MASH) 1-1-1 分频器控制器的分数 N 电荷泵 (CP) PLL 显示出成对的杂散音调，称为“喇叭杂散”。该现象已在商用宽带合成器的测量中得到证实。本简报介绍了对该现象的分析以及缓解该现象的技术。MATLAB 仿真结果显示了具有三阶 MASH 数字的 II 型 CP-PLL $\Delta \Sigma $ 调制器 (DDSM) 来验证所示的技术。还提供了测量结果。