On Optimum Digital Phase-Locked Loops

This paper gives the design procedure of optimum digital filters for analog-digital phase-locked loops. The inputs considered are the step and ramp change in phase. The digital filters can easily be realized on the digital computer or otherwise. Design curves are given to choose proper noise bandwidth, sampling period, and loop parameters. It is shown that the optimum digitalanalog phase-locked loop is not the discrete version of the optimum continuous phase-locked loop.