Noise Compensation Limits of a Linear Frequency Synthesizer Model with a PLL System with a Frequency Feedback Loop

Modern communication systems put high requirements to the spectral purity of a signal. Existing frequency synthesizers, based on indirect synthesis systems, may not always meet these requirements. An additional phase noise compensation loop can be added to the Phase Lock Loop system, designed to increase the spectral purity of a signal. However, such a system is not always stable and enough fast. This article describes the problem of determining the limit of phase noise compensation while maintaining system performance.