关键词: &pi, 网络法, 石英晶片, 直接数字频率合成器, 实验教学系统

Abstract:

Quartz Crystal (QC) is the foremost electronic component, the physical parameter measurement of which has a direct influence on the quality of electronic products. An equivalent circuit model of quartz crystal is established by taking into account the impact of the actual air gap; the formula is derived from the effect of the air gap on the measurement error, which can become the major error compensation basis; and then the physics experiment system for the whole quartz crystal (QC) parameter measurements is developed using the π network. A direct digital synthesizer is acted as the stimulate source, and microcontroller AT89C52 is used as the controll unit. The physical parameters such as the resonate frequency, the relative activity, the spurious coefficient are obtained by the current response measurement of QC in the π network. The ISA bus interface is acted as the communication interface of PC and controller, and data processing and logic control are implemented by the PC software which uses multiprocess techniques in the platform of Visual C++. The practical results show it possesses the same precision and performance as the same type of systems, and it has been used as the experimental teaching system of Electronics.

Key words: &pi, network method;quartz crystal;direct digital synthesizer;experiment teaching system