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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