Imaginary component Dispersion-mode

As stated in Section 7-4b, digital resolution in the v domain is a function of the number of increments (ni) and the spectral width (swi). Spectral data describing the v dimension can be acquired in the either the phase-sensitive or the absolute-value mode. Real and imaginary ui-domain data sets exist for both types of acquisition, but are treated differently. The imaginary data are discarded in phase-sensitive acquisition, just as with the V2 dimension data previously described. By contrast, with absolute-value data, both the absorptive (real) and dispersive (imaginary) components of the v domain are used to describe the spectrum. The important point is that, for both kinds of data, the acquisition of 2M increments yields M points, after Fourier transformation, to characterize spectra in the ui dimension. Therefore, if swi = 2,100 Hz and ni = 512, then DR = swi/(ni/2) = 2,100 Hz/(512/2) = 8.2 Hz/point. If one level of zero filling is carried out, then the effective ni = 1,024 and it follows that DRi = 2,100 Hz/( 1,024/2) = 4.1 Hz/point. 

Although this eliminates negative contributions, since the imaginary part of the spectrum is also incorporated in the absolute-value mode, it produces broad dispersive components. This leads to the broadening of the base of the peaks ( tailing ), so lines recorded in the absolute-value mode are usually broader and show more tailing than those recorded in the pure absorption mode. 

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