Fracitonal N PLL是啥PLL呢？

就是用的分数分频器的PLL

多谢了，看了理解的没错

呵呵，重点是使用delta-sigal来消除低次谐波

也叫小数分频PLL

delta-sigma modulator? yatn, are you familiar with it. How do you deal with the tradeoff between Quantization Noise and bandwith? You use MASH or Culter?

呵呵，不好意思，我也是正在作这个项目，你说的culter是指n/n+1分频器吗?我们这有个牛人建议我不要采用mash，保守的还是使用n/n+1。使用mash的相位开关不好作，容易漏相位。
量化噪声主要是看delta-sigma的阶数吧?我觉得delta-sigma的作用是有限的。主要还是看bandwith吧?bandwith越窄，效果越好吧?不知道我说的对不对 ，有时间还得多情教你！

回复 #7 yatn 的帖子
MASH是sigma－delta modulator的一种结构吧。在国内大部分都用的是三阶MASH结构。至于tradeoff between Quantization Noise and bandwith，是怎么回事?
bandwidth是PLL的带宽吧，sigma－delta只是将量化噪声推向高端，然后通过PLL的低通滤波器将噪声滤掉。

好令人佩服啊！

嗯，pfho解释的真好谢谢了！

有道理啊
MASH和Culter谁再解释下?

mash的漏相位是什么意思，有谁能解释一下,3x

有点搞不懂了，初学

In my opinion, Fractional-N PLL based on the sigma-delta modulator have a tradeoff between bandwidth and the phase noise, which is the drawback of Integer-N PLL rather than Fractional-N PLL. because the bandwidth is related to the frequency of the reference signal, and the Fractional-N PLL are available to change the frequency of the reference signal to gain a specific frequency resolution.

In my opinion, Fractional-N PLL based on the sigma-delta modulator have a tradeoff between bandwidth and the phase noise, which is the drawback of Integer-N PLL rather than Fractional-N PLL. because the bandwidth is related to the frequency of the reference signal, and the Fractional-N PLL are available to change the frequency of the reference signal to gain a specific frequency resolution.

小数分频pll