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Using Resonance Elimination

Using Resonance Elimination

NUTS Help

Using Resonance Elimination (RE)

This subroutine fits an FID with a single frequency and then subtracts the calculated FID from the data. The FID must be dominated by a single resonant frequency near zero. Because the calculated FID will have ideal Lorentzian lineshape, the quality of the fit is critically dependent on the lineshape of the data.

Note that RE is not included in NUTS Lite.

 

This spectrum has a very large peak at the center (0 frequency) and some small peaks very close to it. The goal is to remove the large peak without affecting the smaller ones.

(This is actually simulated data, with ideal lineshape.)

 

On entering the RE subroutine, a first guess at a matching FID is displayed

 

These parameters can be adjusted to give a closer starting point by selecting Edit Parameters from the Edit menu, or typing E.

This dialog box shows the parameters which are adjusted during the fit.

 

To initiate the fit, select Fit to Data from the Edit menu, or type F. The Simplex fit may take a couple of minutes.

When the fit is completed, select Delete Calculated Resonance from the Edit menu, or type D.

 

After FT, the major peak is removed. A small negative peak remains, because the fit was not perfect.

 

Comparison of spectra without (top) and with RE, using the Dual Display utility.

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Last updated: 12/12/03.