Oscillator aging refers to very small changes in the frequency of the crystal oscillator over the lifespan of the device. Aging in crystal oscillators can be accelerated by changes in the physical size of the crystal in its manufacturing and packing processes or stress-induced from changes in temperatures and other environmental factors. The more stress and external pressures applied to an oscillator outside of its specified range, the faster the acceleration of the oscillator aging process and reduction in the usable lifespan of the electronic device. For high-quality crystal oscillators, such as Crystal Oscillator offered by SCTF,the aging rate of crystal oscillator is ±3ppm per year.