Quartz crystal oscillator can be told from the function classification, which could be divided into cspxo standard frequency crystal oscillator, VCXO voltage-controlled crystal oscillator frequency, TCXO temperature compensated crystal oscillator and OCXO temperature crystal oscillator, etc. On the application scope, quartz crystal oscillator is widely used in consumer, communication, industrial, auto electronics industry, and at this stage in all areas of the use of quartz crystal oscillator products are put forward in different requirements.

In the communications industry, the requirements of quartz crystal oscillator frequency increase at the same time with the improvement of communication frequency and bandwidth. Meanwhile, it is stressed that the quartz crystal oscillator phase noise and phase jitter must be reduced, to meet the demand of the quality of communication. In automotive and industrial applications, often face with harsh working environment, such as high temperature, so the reliability of the quartz crystal oscillator is put forward higher requirements. And in the field of consumer electronics, in addition to the miniaturization of products, we must consider cost optimization to meet the fierce market competition.