The Calibration Of Testing System And Data Model Analysis For The Dynamic Frequency Temperature Characteristics Of Crystal Oscillator

Quartz crystal oscillator(abbreviation:crystal oscillator)as a frequency source of electronic systems and equipment is widely used in the fields of communication,navigation,instrumentation,and life electronics.Temperature and frequency stability is one of its important performance indicators.Modern high-end electronic products have increasingly higher requirements for crystal frequency stability and accuracy.Especially,the frequency drift of the crystal due to the transient thermal effect of the circuit will seriously affect the performance of the product and improve the performance of the crystal.Dynamic temperature and frequency stability is particularly important.In order to realize the dynamic temperature compensation of the frequency of the crystal when the temperature changes rapidly,a high-precision dynamic temperature-frequency characteristic test system must be developed.The design,analysis and correction of the crystal temperature measurement circuit studied in this dissertation,as well as the data model analysis of the crystal's dynamic temperature-frequency characteristics are important components of the system.The system requires high measurement accuracy of the crystal temperature.Calibration is mainly to solve the problems of temperature drift of the constant current source chip,system measurement error and circuit measurement noise caused by the charging process of the circuit during current switching.Under this premise,a hardware circuit correction scheme suitable for this system is designed.The test circuit is calibrated within the operating temperature range to achieve temperature compensation,and the fixed resistance calibration is used to achieve DAC current switching compensation.The basic theoretical basis of circuit correction is polynomial fitting.Power frequency interference noise reduction uses digital filtering.After correction,the crystal temperature measurement accuracy can reach ±4m?,which meets the system's requirement for measuring the dynamic temperature of the crystal.The analysis and modeling of the crystal frequency and frequency test data includes the modeling of the temperature and frequency characteristics of the thermosensitive crystal at quasi-static temperature(<0.1?/s).The basic theory is the least squares nonlinear characteristic curve fitting.Thermal-sensitive crystal dynamic temperature-frequency characteristic extraction in the range of-5?+5?/s temperature change rate,identification and recording of frequency micro-jumps,local and global thermal hysteresis characteristic extraction and mathematical description,the theoretical basis is ELM neural network The optimization algorithm realizes dynamic temperature compensation of frequency.After verification,the frequency error stability of the crystal can reach ±0.05?±0.08ppm under the temperature change rate of ±1?±5?/s after compensation.The application of the test system and the supporting compensation algorithm can realize the rapid calibration of the dynamic temperature and frequency characteristics of the crystal oscillator,and effectively improve the frequency stability of the crystal frequency component under the rapid temperature change.