A Real-time On-line Automatic Measuring System For Microcomputer Compensated Crystal Oscillator

Since the birth of quartz crystal oscillators, the superior performance makes itwidely applied in various fields. Among the many types of quartz crystal oscillators,the microcomputer compensated crystal oscillator, as a new kind of advantages atfrequency stability, start preheating time and powerful competition, but the limitationsof measuring the temperature-compensated voltage curve greatly hindered thedevelopment of MCXO. In order to achieve the industrialization of MCXO bitterly, areal-time on-line automatic debugging and measuring system for microcomputercompensated crystal oscillator (MCXO) is designed. Automatic real-time onlinemeasurement can improve the accuracy of the temperature measurement, the densityof temperature point and compensated voltage accuracy, minimizing systematic errorsof MCXO due to a variety of factors, more suitable for the requirements of MCXOscale production. The article introduced the composition and related functions ofthe system from the overall design, hardware design and implementation, softwaredesign and implementation.The system integrates the S&A4220Temperature Test Chamber, the FCA3000high precision frequency Counter, a Personal Computer, and a special microcontroller based on C8051F061with Multichannels of measuring. The controlprogram on PC is designed by means of LABview. All main technical parameters of MCXO can be measured with this system automatically. Within the temperature range(-40℃to+85℃), the frequency-temperature stability of developedMCXO is±7×108.