Table of contents : 1 Introduction 2 Review of modulation theory 3 The relationship betweenphase jitter and noise density 4 Noise induced frequency modulation 5 Noise in oscillators 6 Frequency multiplier chains 7 The use of phase lock loops 8 Frequency synthesisers 9 The reciprocal relationships between phase noise and frequency stability 10 System phase noise requirements Appendix 1: Summary of important formulae Appendix 2: Noise figure review Appendix 3:The quadrature representation of narrowband noise Appendix 4: The Q of varactor tuned oscillators Appendix 5: The phase noise performance of Gunn oscillators