Fourier-Transform NMR (FT-NMR) Definition:

In nuclear magnetic resonance (NMR) spectroscopy, a technique in which the sample is irradiated with a short pulse that covers the entire range of relevant rf frequencies.

Fourier-Transform NMR (FT-NMR) Explained:

When nuclei in a magnetic field absorb and re-emit electromagnetic radiation. The energy resonates at a certain frequency according to what atom it is and what it’s characteristics are.

All this can be observed through NMR spectroscopy.