Crystal Oscillator Ads Simulation Optimization And Design

Crystal oscillator is usually used as frequency signal source, which can produceoscillation steady and high-accuracy signal. It’s widely used in those fields, such asprecision electronic equipment, wireless communication and radar, etc. However, withthe development of electronic technique, the phase noise of oscillator has become themajor limiting factor for system performance. So, for practical purposes, this paper willdesign a low-noise oscillator with computer’s aid.We always hope to predict the phase noise in oscillator through computer simulation,this work will supply a direction for our analysis and design on oscillators. In this paper,firstly we analyse the operating principle of oscillator and three basic oscillation circuits.Then we deduce the characteristics and regular of phase noise in high Q crystaloscillator from the Leeson model. Further research will be focused on the reason thatcause the difference between computer simulation and actual measurement, that isdevice parameter influencing flicker noise. Take a100MHz Butler oscillator as anexample, the phase noise curve could be obtained and optimized by the ADS(AdvancedDesign System) with the consider ofA fandK f. Finally, we worked out the real circuitfrom the computer simulation result and got the measured phase noise curve with thehelp of Agilent E5052B. The phase noise level is about-124.0dBc/Hz@100Hz,-153.4dBc/Hz@1kHz and meet the engineering requirements. A good agreementbetween simulated data which consider the device parameters and Leeson model wasachieved.