TAKE THE GUESSWORK OUT OF PHASE LOCKED LOOP DESIGN.

Phase locked loop (PLL) systems are being used today in an ever-increasing number and variety of applications. However, many users still encounter problems which they do not fully understand. These problems usually fall into two basic areas: dynamic peculiarities, such as excessive overshoot, ringing and extended settling time; and spectral-purity problems associated with sideband suppression, which is a problem particularly apparent in digital frequency synthesizers. This article discusses these two problems and provides a number of suggestions which may be used to avoid them.