Pulsed phase-locked loop technology improvements for greater accuracy and expanded capabilities

This paper presents the design for a new pulsed phase-locked loop (PPLL) instrument. Earlier phase detection methods are analyzed for potential error sources, and an alternative phase detection method with fewer sources of error is described. This alternative method of phase detection is incorporated into a fully automated PPLL instrument. Data taken with the new system is compared to data taken with an earlier PPLL instrument. This comparison shows that the alternative phase detection does reduce error. The control loop is analyzed for stability and optimization, and a method of automating this optimization is presented. A method of wave-form acquisition using the automated PPLL that permits automatic location of the received echo is also described.