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Smoke and Mirrors: Ultra-Rapid-Scan FT-IR Spectrometry

The system electronics are simply a PCI-bus analog-to-digital converter board and a personal computer to power it and accept the data. It would be preferable to have a 15 MHz board so that the highest laser modulation frequency would not exceed the Nyquist limit. As of this writing, 14-bit A/D converters of this speed are not yet available. A PCI bus might be strained by a data rate of 60 megabytes per second. As it is, the 20 megabytes per second fills memory very quickly. The reason that no polymer stretching measurements are included here is that a 12-gigabyte disk drive that can accept data at 20 megabytes per second will be required to store the data for post-processing. An alternative to recording to disk is to co-add or transform and co-add in real time. The price of DSP boards capable of 1 billion+ floating point operations per second has recently become quite reasonable.

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