论文部分内容阅读
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。
The measurement of mechanical properties (such as Young’s modulus, density, thickness, etc.) of film materials by laser surface acoustic wave (SAW) technology has been more and more widely used. However, laser-excited laser detection of surface acoustic waves (LG / LD-SAW) has a wide spectrum bandwidth (up to several hundred megahertz to GHz), and the general detection method is difficult to detect such a high bandwidth. A weak signal processing circuit based on the principle of lock-in amplifier (LIA) is designed. By using a special denoising circuit, weak signals can be detected over a wide frequency range (GHz) and extracted from the noise signal .