激光干涉系统中若干信号同步问题的处理技巧

介绍了基于压电陶瓷(PZT)的激光干涉系统中若干信号同步问题:首先,针对采集卡 D/A 驱动 PZT 和 A/D高速采样二者的同步处理,介绍了分别利用 Visual C++改进软件算法和软硬件相结合实现同步的两种方法,并通过绘制 PZT 线性特性曲线比较两种同步方法的优劣;其次,针对常用采集卡对多路信号的采集是异步的,且采样频率越低,误差越大的问题,通过增加采集卡模拟量输入(IA)通道使用数目的方式,对四象限光电管四路信号进行对称布置的方法消除采样间隔引起的误差,实现相邻象限相差的高精度识别,同时起到了一定的滤波作用;最后,利用频谱特性分析了移动平均的滤波效果.实验结果表明该同步技巧能较大提高相差的识别精度,滤波算法能较好滤去背景光强及光电子器件引起的噪声.

Skills of Several Signal Synchronization Problems in Laser Interferometer System

Several signal synchronization problems based on piezoelectric ceramics (PZT) of laser interference system have been described. Firstly, as for D/A of collection card to drive PZT and A/D high speed sampling, two methods are described respectively. One is using Visual C++ by improved software algorithm to implement synchronization and the other combines hardware and software to implement synchronization. And PZT linear characteristics curve is drawn to comprise pros and cons of two synchronization method. Secondly, for common collection card with several channels is asynchronous, and the lower sampling frequency is, the larger the errors is, by the way of increasing Analog Input (IA) channels, symmetric layout sampling channels are used to eliminate errors because of sampling interval, which can realize high precision adjacent quadrant phase difference. Meanwhile, it has some effect on filter. Lastly, moving average is analyzed by spectrum characteristic. Experimental results indicate that the way of synchronism will improve the system measurement precision of phase, and filtering algorithm can filter background noise caused by light intensity and optical electronic devices.