A Method for Analysis of Phase-Locked Servo Systems

General considerations, limitations, and design parameters for dc motor control using phase-locked loop techniques are described". Functions of individual loop elements for best dynamic system performance are discussed. Generalized continuous linear block scheme of such servo system suitable for tracking analysis is developed to describe the system behaviour during long term speed variations. Generalized linear discrete block scheme of such servo system suitable for acquisition analysis is also introduced to describe the behaviour of the system during instantaneous speed variations. Also discussed are the design requirements and the main problems encountered in the design. These include the system band-width, the lock range, compensating circuit parameters and system gain for critical stability, and system accuracy.