THE EFFECT OF A PURE TIME DELAY ON THE STABILITY OF A PHASE-LOCK LOOP

摘要

This report discusses in detail the effect of "transport lag" or pure time delay in the feedback loop of a phase-loclc control system. The system analysed is that which controls the relative phases of several transmitters to provide e coherent signal at a satellite. The report first derives the equation of the control loop, line arises the resulting differential-difference equation, considers the loop to have unity compensation, and proceeds to discuss the solution. , The results of this analysis are that, for stable operation, the loop gain may not exceed for a time delay of T seconds, which results in a steady-state phase error of.