一种基于虚拟仪器技术的双锁相放大器的设计

摘要

锁相放大器是微弱信号检测的最有效手段,针对现有模拟锁相放大器和数字锁相放大器存在的问题,利用虚拟仪器技术和锁相放大器的基本原理,基于NI公司的LabVIEW软件及DAQ板卡对数字锁相放大器进行设计.设计中采用双锁相技术,通过在紫外辐射测试中的测试结果表明此锁相放大器具有更好的性能,可以精确地提取被噪声湮没的信号,可获得较好的信噪比.%Lock-in amplifier( LIA) is the effective means for weak signal detection. For existing analog and dig ital LJA problems, the double lock-in amplifier is designed based on LabVIEW and DAQ as well as virtual in strument and principle of LJA. The dual-phase PLL is adopted in this design. It is proved through application in detect of ultraviolet radiation that this software LIA is better in performance than conventional LIA. It can get out the annihilation signal by the noise precisely and gain a better signal-to-noise ratio.