FID Truncation and Spectral Artifacts

Truncation artifacts are rarely a problem in H NMR, because acquisition times usually are long enough (2-4 s) to permit essentially complete decay of the FID. The 

Several terms pertaining to resolution are used widely in NMR spectroscopy. It is appropriate to define them further at this point to avoid confusion. Spectral resolution (SR) concerns the acquisition time employed to acquire the spectral data. We saw in Section 2-4 (introduction) that this number is the reciprocal of and is expressed in Hz. If np — 32,768 and sw = 4,000 Hz, then = 4.1 s, and SR is given by 

Digital resolution (DR) is related to both sw (in Hz) and the number of points actually used to describe the final Fourier-transformed spectrum. DR is an important concept because the distinction between two signals whose separation is Av (the signals can be two single lines or a coupling constant) necessitates a DR of about (Ai ) [e.g., for Av 1 Hz, 

With the very large data sets currently used in one-dimensional experiments (32 or 64 K), digital resolution is seldom a problem. Equation 2-3 also demonstrates that SR and DR are the same. Both are derived from eq. 2-1 in Section 2-4d. DR, however, provides the entry to zero filling and the recovery of lost data points (Section 2-5b). Again, for the previous SR example, with one level of zero filling to 65,536 total points, we have 

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