Dear tulip,

> what is "the track and filter" main in the conclusion : "Within the PLL's loop bandwidth, the PLL
> can successfully track and filter the LDO noise, reducing its contribution."

The phase of the output clock of a phase-locked loop will follow the phase of its input reference clock when the frequency of its phase disturbances are less than the bandwidth of the phase-locked loop. Hence, the statement from Analog Device's Analog Dialogue indicates that as long as the phases disturbances of the LDO has frequency components less than the bandwidth of the phase-locked loop, the phase-locked loop will attenuate phase disturbances due to the LDO.

Does this help tulip?

smlogan