In the observer-controller digital phase-locked loop (DPLL), the loop filter is designed in the time domain, instead of using poles and zeros in the frequency domain as in the conventional DPLL. The primary advantage is that it provides additional degrees of freedom that may be unavailable in the frequency domain approach. This paper reviews existing work on the observer-controller DPLL and the advantages that it provides, namely its ability to explicitly model and compensate for the effects of loop latency and supply noise.
['Won Namgoong']
An observer-controller digital PLL — A time-domain approach