【摘要】 利用激光声表面波(SAW)技术对膜材料机械特性的测量(如杨氏模量、密度、厚度等)已得到了越来越广泛的应用。但激光激发激光检测声表面波(LG/LD-SAW)的频谱带宽较宽(达几百兆到GHz),一般的检测方法难以在如此高的带宽下对其进行检测。设计了一种基于锁相放大(LIA)原理的微弱信号处理电路,通过应用一特殊的去噪电路,能在很宽的频谱(GHz)范围检测微弱信号,并将其从噪声信号中提取出来。更多还原

【Abstract】 Laser surface acoustic wave(SAW) technology for measuring thin film mechanical properties such as Young’s modulus,density,thickness,and so on,has been widely used.However,due to wide spectrum bandwidth(up to several hundred MHz to GHz) of laser-generate and laser-detecting surface acoustic wave(LG/LD-SAW),general methods can not detect it in such a high bandwidth.A weak signal processing circuit based on lock-in amplifier(LIA) is proposed,and it achieves GHz detection of weak signals through using a special de-noising circuit and it can be extracted from noise signal.更多还原