Difficulty: Easy
Correct Answer: A mathematical transform (Fourier transform) to convert time-domain data into a frequency-domain spectrum
Explanation:
Introduction / Context:
NMR instruments record a free induction decay (FID), a time-domain signal produced by precessing nuclear magnetization after an RF pulse. To extract meaningful resonance frequencies and intensities, the FID must be mathematically converted into a spectrum that displays peaks versus chemical shift (ppm).
Given Data / Assumptions:
Concept / Approach:
The Fourier transform (FT) converts time-domain signals into frequency-domain representations, revealing individual resonance frequencies and line shapes. This transformation underlies virtually all modern NMR spectroscopy and MRI image reconstruction (with additional spatial encoding). Without FT, the complex overlapping time signal would be very difficult to interpret.
Step-by-Step Solution:
Verification / Alternative check:
Comparing raw FID to processed spectra demonstrates that discrete peaks only appear after FT; this is standard in all commercial NMR software suites.
Why Other Options Are Wrong:
Common Pitfalls:
Confusing the hardware magnet strength (MHz) with data processing; both matter, but spectral understanding arises from FT of the FID.
Final Answer:
A mathematical transform (Fourier transform) to convert time-domain data into a frequency-domain spectrum
Discussion & Comments