Analysis And Modeling Of Oscillator Phase Noise

Oscillator is an important modern in communications equipment and military equipment, radar and other important circuit module. Phase noise performance as the most important indicators of the oscillator has important research value. Therefore, an accurate phase noise model of a simple, used to guide the low phase noise oscillator design and improve the quality of modern communication and radar performance, is important.After years of research, scholars have produced some very valuable model. On the one hand, we have to study the existing model, modify one of the imperfections. On the other hand, we need to build a new model. Because of phase noise modeling requires extensive engineering experience and deep theoretical guidance, so the research of phase noise in domestic started late, and the level is relatively low. Our scholars are working on absorbing the valuable model or the amendments of the model. Whether the simple model of common D.B.leeson or the complexity of the nonlinear disturbance model by A.Demir and his partner have an understanding of domestic scholars, but for this new, simple and accurate nonlinear phase noise analysis method does poorly understood. So this paper, the new method is described in detail and verified, so that more people can pay attention to this phase noise analysis method and improve it.At the beginning of the paper, what is the phase noise discussed in detail. Phase noise reflects the frequency purity of frequency source, is the representation of phase jitter of time domain in frequency domain. Then establish the relations between time-domain jitter and phase noise. And then through several circuit examples, which illustrate the impact of phase noise on the circuit, proves the need for phase noise analysis. From the introduction of study history done by foreign scholars about phase noise, we can know the target of phase noise analysis. In general, with the increasing accuracy of the model, the research goal has been changed to simplify the model. For a particular oscillator circuit, through a deep understanding of the circuit, propose a simple and accurate model of the phase noise is the main objective.Then, according to the accuracy of each model, the paper in turn describes several widely used phase noise model. Through a detailed derivation of each model, shows the advantages and the existing shortcomings of each model. From the simple linear time-invariant model to the relatively complete nonlinear time-varying model, the model gradually is optimized, and becomes very accurate. Because it needs the circuit abstract and a lot of knowledge about mathematical statistics, the analysis process becomes more complex and beyond the grasp of the general capacity of the circuit design engineer.Based on previous studies, and the inadequacies of the existing phase noise analysis, we introduce the nonlinear phase noise analysis method. Although this method can only be applied to the analysis of LC oscillators, but it is very simple and easy to understand. Nonlinear phase noise Analysis method makes the analysis of the process greatly simplified by introducing a important circuit principles, so it is ideal for engineering design. Through a series of theoretical derivation, the final non-empirical parameters obtained analytic phase noise. Because no parameters, which need simulation or measurement,so both can be used to calculate the circuit's phase noise, and can be used to guide how to reduce phase noise.Then in the thesis, through the actual circuit simulation on the nonlinear model proves the validity of this analysis method. Because the result got from nonlinear phase noise analysis method is an analytical formula, it is natural to be used as the guide of how to reduce the phase noise. The article points out several of the phase noise reduction method, model calculation results compared with the simulation results, proving once again that nonlinear phase noise analysis method is reasonable and valuable.Finally, the nonlinear phase noise analysis method is summarized. In LC oscillator circuit the importance of the nonlinear characteristics and time-varying characteristics is compared. In some oscillator such as cross-coupled LC oscillator nonlinear characteristics should be more important than time-varying characteristics, so the nonlinear phase noise analysis method has important research value.