A novel stability analysis of a PLL for timing recovery in hard disk drives

Timing recovery in hard-disk-drive data transfer is an increasingly critical problem due to the growing data rate to be supported. We present a novel approach to the stability analysis of a high-order digital phase-locked loop (PLL), addressing the specific application. We find the value of the integrating and proportional open-loop gain leading to stable behavior. The analysis was developed in both the digital and analog domains and the obtained results are compared. The stability analysis in the unified transforms domain is also developed, showing that it matches the results obtained with both discrete and continuous-time analysis