设计了一种针对频率扫描绝对距离测量系统的信号处理算法。该系统采用基于电流调制式的频率扫描方法,利用一个比对干涉光路与一个测量干涉光路进行同步测量。两路扫描干涉信号分别由两个光电探测器进行光电转换,作为绝对距离计算处理的输入信号。分析TN量系统的原理与扫描干涉信号的特点,应用两步差分卷积算法进行信号处理,提取的比对光路与测量光路的周期或频率信息进行绝对距离测量。分析了该算法的周期计算误差。实验验证这种方法具有较大的计算优势。
A signal processing algorithm is designed for the absolute distance measurement system performed with frequency-sweeping interferometry. The system adopts frequency scanned method based on current modulation, and a comparing optical path and a measuring optical path are used to measure synchronously. The two interference signals are converted into electrical signals by two photodetectors and are used as input signals for absolute distance calculation. The principle of the measuring system and the characters of interference signals are presented, the difference smoothing convolution is used for processing the signals twice and the absolute distance is determined by the period or frequency information extracted from interference signals produced while scanning the laser frequency. The period calculating error of this algorithm is analyzed. The experiment results demonstrate that this method has major computing advantages.