Abstract: In order to measure the resonant frequency and the quality factor of quartz-enhanced photoacoustic spectroscopy gas sensing system, to serve the teaching requirements of R-L-C frequency selection circuit in the ourse of “ high frequency electronic circuit冶, to and promote the full integration of teaching and scientific research, a frequency sweep and performance test experimental system for quartz tuning fork is designed and implemented. The principle of R-L-C electrical model of quartz tuning fork is firstly analyzed, and the model is simulated by Matlab. In order to amplify the output signal of a quartz tuning fork under sinusoidal excitation or external sound field, a transimpedance amplifier circuit is designed. The frequency sweep and performance test system of quartz tuning fork is established by using a lock-in amplifier, a trans resistance amplifier, a signal generator and a LabVIEW signal platform. Using the given quartz tuning fork, the equivalent circuit model parameters, resonant frequency and quality factor are tested under vacuum packaging and shell removal. This system integrates the basic knowledge of R-L-C frequency selection circuit and expands the scientific research application cases based on quartz tuning fork. The practical application shows that the system can meet the experimental teaching requirements of R-L-C frequency selection circuit and scientific research needs of quartz enhanced photoacoustic spectroscopy technology, and has achieved good teaching and research application results.

Key words: experimental teaching system, R-L-C circuit, quartz tuning fork, quartz-enhanced photoacoustic absorption spectroscopy, LabVIEW