Fixed Pulse Width Phase Correction Logic for Digital Phase-Locked Loop
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
This article describes a technique for using a digital phase-locked loop having a fixed pulse-width single-shot pulse for correcting phase error in a variable control oscillator when there is no data pulse to lock on to. The previous circuits used in the art solved the problem of obtaining phase lock where data pulses were missing, by locking to the falling edge of each existing data pulse and providing a single-shot pulse width that varied such that it would equal and track to the varying VCO pulse width. However, it is difficult to design an integrated circuit logic a single shot having a pulse width which has to vary and the logic necessary to have the pulse width tracked to another varying pulse width. (Image Omitted) The present circuit illustrated in Fig. 1, enables a phase arrangement such as that as illustrated in Fig.