Computer aided design of quartz crystal oscillators

摘要

The latest development of a simulation program designed for quartzncrystal oscillator analysis is presented in this paper. The simulatornbeing developed uses the full nonlinear Barkhausen criterion method. Itnconsists of finding the frequency Ω0 and the amplitudenu0 which nullify both the real and imaginary parts of ancharacteristic complex polynomial P(u,jΩ) describing thenoscillator behavior. Most of the nonlinearities come from the amplifyingntransistor described by using large signal admittance parameters y(u)nobtained by means of an analog circuit simulator (SPICE). This papernpresents the method used to derive and code the characteristicnpolynomial coefficients. This method has been successfully implementednfor a Colpitts oscillator and is currently being used to build annoscillator library covering the most widely used structures. Thenvalidity and the predictive power of the model have been checkednexperimentally and the comparison between experimental results andnsimulation is presented and discussed