High‐speed digitizer/averager data‐acquisition system for Fourier transform electron paramagnetic resonance spectroscopy

Autor:	Frank Harrington, Murali C. Krishna, Rolf Tschudin, Hal A. Fredrickson, Sankaran Subramanian, Joseph F. Fessler, John Bourg, Thomas Pohida
Rok vydání:	1994
Předmět:	Adder Materials science Spectrometer business.industry Noise (signal processing) Signal symbols.namesake Fourier transform Data acquisition Nuclear magnetic resonance Optics Parallel processing (DSP implementation) Personal computer symbols business Instrumentation
Zdroj:	Review of Scientific Instruments. 65:2500-2504
ISSN:	1089-7623 0034-6748
DOI:	10.1063/1.1145223
Popis:	A high‐speed digitizer/averager data‐acquisition system designed and built as part of a 300‐MHz Fourier transform electron paramagnetic resonance spectrometer is described. There are two key features of the system: (1) the maximum digitizing rate is 300 Msamples/s and (2) a 256‐point free‐induction‐decay signal running summation can be updated in less than 3 μs. At the maximum digitizing rate, the system can sum 65 536 FIDs in 220 ms. The system consists of an analog‐to‐digital converter/adder unit (ADCA) and an IBM compatible personal computer. The ADCA is comprised of a digitizer, high‐speed sample buffers, high‐speed adders/memory, and control hardware. Design techniques, such as parallel processing, utilized to meet the high‐speed performance requirements are described. Trigger and timing signals for the system are derived from the spectrometer. System efficiency, synchronization, and time base stability are demonstrated in the spectrometer at a sampling frequency of 200 MHz. Signal‐to‐noise ratio enhancements are shown using a lithium phthalocyanine test sample.
Databáze:	OpenAIRE
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