Design and Implementation of Calibration Circuit for Crystal Oscillator

High performance crystal oscillator is usually used as the clock source of system timer in a miniaturization space aircraft, however, it cannot overcome the effect of long-term aging on accuracy. Thus, this paper presents a simple, light and efficient circuit to calibrate the difference between the actual output frequency and the nominal frequency of a crystal oscillator periodically in real time. The experiments show that the proposed design reduces the timing deviation from more than 1614ms to less than 1ms in 5 hours. The timing error is less than the required error index, which gives strong support to the working timer of a space aircraft.