PFD(全称:Phase-Frequency Detector,即鉴频鉴相器)对参考时钟(ref_clk)频率和需要比较的时钟频率(即上图中的输出时钟:pll_out)进行对比。 2、PFD 的输出连接到 LF(全称:Loop Filter,即环路滤波器)上,用于控制噪声的带宽,滤掉高频噪声,使之趋于一个稳定的值,起到将带有噪声的波形变平滑的作用。如果 PFD 之前...
而如何将高频分量去除并把相位的误差信息转换为DDS的相位控制信号呢(在模拟域则为压控振荡器的相位控制信号),这里就需要环路滤波器(loop filter)出场了。 环路滤波器(loop filter) loop filter的功能就是将鉴相器输出的误差信号的高频信号滤除并转换为DDS的相位控制信号,在数字域很自然的会想到FIR+cordic算法。通过...
A loop filter’s bandwidth can be doubled by doubling either the PFD frequency or the charge-pump current. If the actual Kv of the VCO is significantly higher than the nominal Kv used to design the loop filter, the loop bandwidth will be significantly wider than expected. The variation of...
The PLL is a fully programmable, ultra-flexible design and is intended to be used for jitter cleaning of the noisy input clock. The PLL uses a semi-digital architecture and there is no need for external loop filter. The loop-filter has separated integral and proportional paths, which can ...
PLL内部的功能框图如下图所示:Logos PLL 主要由鉴频鉴相器(PFD,Phase Frequency Detector)、环路滤波器(LF,Loop Filter)和压控振荡器(VCO,Voltage Controlled Oscillator) 等组成。通过不同的参数配置,可实现信号的调频、调相、同步、频率综合等功能。 LogosPLL 的电路框图如下图所示: 想了解更多的时钟配置, 建议...
The DPLL is a digital loop filter/controller designed to be used in conjunction with Silicon Creations Fractional-N PLLs. The resulting dual-loop PLL can attenuate jitter in extremely noisy reference clocks (and "gapped clocks" such as in OTN SerDes repeater/switch systems) and multiply very ...
PLL内部的功能框图如下图所示:Logos PLL 主要由鉴频鉴相器(PFD,Phase Frequency Detector)、环路滤波器(LF,Loop Filter)和压控振荡器(VCO,Voltage Controlled Oscillator) 等组成。通过不同的参数配置,可实现信号的调频、调相、同步、频率综合等功能。 LogosPLL 的电路框图如下图所示: ...
那么使用National Clock Desige Tool ,如何实现Single PLL模式呢 ? 另:PLL2 的Loop Filter 2,缺省是4th order , 没有2th order ,3th order ? codeloader下载地址:http://www.ti.com/tool/codeloader 哦,我的意思就是:在PC里,使用Code Load生成配置参数之后,是要下载到LMK04803芯片里的,那么这个...
PLL内部的功能框图如下图所示:Logos PLL 主要由鉴频鉴相器(PFD,Phase Frequency Detector)、环路滤波器(LF,Loop Filter)和压控振荡器(VCO,Voltage Controlled Oscillator) 等组成。通过不同的参数配置,可实现信号的调频、调相、同步、频率综合等功能。 LogosPLL 的电路框图如下图所示: ...
A deep insight into the derivation of the PLL's small-signal model, main characteristics, stability analysis, and loop filter design are discussed in this paper. The main advantages of the proposed method are explained in terms of several performance indexes, such as settling time, steady-state...