New approach to high-precision Fourier transform spectrometer design
New approach to high-precision Fourier transform spectrometer design
复制标题
DOI：
10.1364/ao.35.002891
复制
发表时间：
1996-06-01
期刊：
影响因子：
1.9
通讯作者：
Brault, JW
中科院分区：
文献类型：
--
作者：
Brault, JW
在干涉光谱测量中，激光条纹长期以来一直被用来确定x轴，但强度轴的解决方案并不令人满意。现在，我们看到针对立体声音频应用而开发的低成本、中速、Σ-Δ模数转换器在商业上的快速发展。一个芯片提供两个20位精度的通道，频率为50 kHz，这是对许多成本和复杂性更高的当前系统的重大改进。但是，虽然激光器在空间域中工作，但该转换器严格地在时域中工作;它不能被触发。我已经开发了这两个领域之间的桥梁，自适应数字滤波器，它不仅允许我们使用这个转换器来获得测量在任意时间，但作为奖金，告诉我们如何移动的干涉控制和数据采集系统的复杂性从硬件到软件。例如，灵活的条纹细分（以增加自由光谱范围）很容易获得一个简单而有效的算法，完全没有激光鬼。对驱动速度变化的补偿也是可能的，只需要适度增加计算机存储器。
Laser fringes have long been used to establish the x axis in interferometric spectrometry, but solutions for the intensity axis have been less satisfactory. Now we are seeing the rapid commercial development of low-cost, medium-speed, sigma-delta analog-to-digital converters developed for stereo audio applications. A single chip provides two channels of 20-bit precision at 50 kHz, a significant improvement over many current systems of much greater cost and complexity. But while the laser works in the spatial domain, this converter operates strictly in the time domain; it cannot be triggered. I have developed a bridge between these two domains, the adaptive digital filter, which not only permits us to use this converter to obtain measurements at arbitrary times but as a bonus shows us how to move much of the complexity of an interferometric-control and data-acquisition system from hardware to software. For example, flexible fringe subdivision (to increase the free spectral range) is easily obtained with a simple and efficient algorithm, completely free of laser ghosts. Compensation for drive velocity variation is also possible, requiring only a modest increase in computer memory.