Performance trade-offs between Type II and Type III PLLs

Practical designs of Type III PLL are scarce, and even they have been sometimes considered impossible. In this paper we present for the first time a performance comparison between Type II and Type III PLLs. The analysis is based on a powerful model previously presented by the authors. In particular the advantages of type III PLLs over type II to follow chirp signals, without compromising stability, are demonstrated. Approximated closed form expressions are proposed to evaluate Type III PLL performance.