APC With Pulse Reference

Abstract

Abstract : Research is concerned with single-loop automatic phase control (APC) systems wherein the reference signal is a periodically repeated pulse for locking the frequency of an oscillator at the pulse rate, or at a multiple thereof. The locked system is analyzed as a linear, sampled regulator in both the time and the transform domains; the latter is used also to analyze the system just outside synchronism. The theoretically determined values of the stability limit and the pull-in ratio are verified experimentally over a wide range of the system parameters. Previous systems suffer from either severe FM (mainly at the pulse rate) or from an undully small control range; it is shown here that synchronism over a substantial portion of the tuning range is possible, and that sidebands arising from the control need not exceed -- 100 db. Moreover, the oscillation spectrum is improved with regard to inherent perturbations that are sufficiently small and slow. Evidence for multiplication ratios as great as 300,000 is presented. Performance of this quality is due in part to the design of a balanced clamp circuit for phase detection. (Author)