A Novel Method of Temperature Compensation for Quartz Crystal Oscillator Based on Digital Resistor

摘要

Temperature compensation is a crucial way in obtaining a high precision quartz crystal oscillator, which is the most important component for frequency and time control. In order to find an accurate and low-cost temperature compensation solution, a novel system was designed by using the DS1847, a new IC chip of digital resistor. In the system, the chip was used to form a voltage divider network to generate a controllable voltage, which was executed on a varactor to realize the compensation purpose. The system only needed an initialization and then it could function without the help of MCU. Because of its simple form and digital output, it was cheap and precise. Experiments showed that the system could achieve a frequency instant stability of 0.015ppm in a second and a frequency difference of 1.7ppm in the temperature range of —20～60°C with a varying rate of temperature 0.5°C/min.