CW or FT technique:

In both the set ups the different protons (nuclei) are brought into resonance one by one by continuously varying either the field or the frequency. Therefore this is called continuous wave (CW) spectrometry. A CW technique was the basis of all NMR instruments constructed up to about the end of the 1960s. By CW is still used in some lower resolution instruments, here most of the modern instruments use pulsed Fourier transform (FT) technique. However, for the interpretation of NMR spectra it does not matter whether the NMR spectrum is recorded by the CW or FT technique.