Design and Analysis of a Linear Phase-Locked Loop of Wide Dynamic Range

Consideration is given to a phase-locked loop configuration which provides a linear control characteristic over a range of 2π radians. Loop configurations employing pulse-amplitude-modulation (PAM) and pulse-duration-modulation (PDM) sawtooth phase comparators are outlined. The performance of the loop in a noise-free environment is determined for the case where the loop filter is of the perfect proportional-plus-integral control type. Expressions for the normalized pull-in time are obtained, and the results are compared with those available for the conventional loop employing a sinusoidal comparator. The limitations of this technique, as well as loop performance in a noisy environment, are also discussed