On the noise behavior of PLL-based frequency synthesizers

Abstract

This work contains a thorough analysis of a PLL-based frequency synthesizer in order to study the effect of electronic noise coming from different intrinsic and extrinsic noise sources. In comparison to the previously done analysis, a more complete combination of noise sources and better modeling techniques are used. An improved technique for analyzing the noise due to different sources in the system is demonstrated. Using an improved mathematical noise modeling technique based on Rice’s noise models, a method is developed that results in the derivation of a very general mathematical model for the output of synthesizers taking into account noise sources at different points in the circuit. A method for calculating the power spectral density for the output of the synthesizer containing the effect of multiple noise sources will be shown. Using the different results from the mathematical considerations, a simulation environment is built to simulate the noise and the dynamic behavior of the system taking into account linear and nonlinear models. Moreover, new results in the noise measurements of frequency synthesizers are shown in this work. A new measurement technique with which it is possible to predict the effects of noise due to different devices on the synthesizer output is presented. An improved low noise power supply which helps to lower the noise floor of critical components in the system like XCO and VCO is shown.