EFFECT OF SAMPLING RATE ON FOURIER-TRANSFORM SPECTRA - OVERSAMPLING IS OVERRATED

The authors explain and demonstrate the effects of oversampling in Fourier transform spectrometry. For Fourier transform interferometry, magnetic resonance, or ion cyclotron resonance mass spectrometry conducted with an ADC of at least 12 bit/word, we conclude that quantization 'noise' is negligible; oversampling thus has little effect on FT spectral signal-to-noise ratio, dynamic range, or resolution. Oversampling can, however, improve phase and magnitude linearity by eliminating the need for a sharp cutoff in the passband of the analog filter. Finally, autocorrelation analysis of simulated time-domain signals shows that quantization 'noise' is random and essentially independent of frequency (i.e., 'white') at practically attainable sampling rates.