Unaliase a peak

An aliased peak can always be unaliased by setting the number of spectral widths that have been added to the peak position to move it to its 'real' peak position. This value may be a negative or positive integer and will expand the contour to cover the ppm values for the aliased peak. The relation between the observed and the 'real' peak position can be described as:

δobs = δ + nSW, where n = ..-3, -2, -1, 1, 2, 3.. is the number of spectral widths that the peak was aliased with and SW is the spectral width. To unaliase a peak, do as follows:

• Select the aliased peak

• Click  R: Peak: Unalias Peak

• Set the number of times that the peak was aliased (n above) in |Num. Aliasing|.

• • Click [OK] in the Query popup to extend the spectral boundaries.

The spectral bounds will now be extended beyond the fundamental region to include the position of the unaliased peak. In addition, in the extended region, Analysis will make a tiled copy of the contours of the fundamental region. When Analysis extends the bounds, it does so by changing so-called minimum and maximum aliased frequencies of a spectrum. These frequencies can be set independently for each dimension of a spectrum, and be used either to cut off the spectrum contour display at a particular value or to extend the contour display to a particular value. The minimum and maximum aliased frequencies are set in the {Referencing} tab in the Experiment: Spectra popup, using M: Experiment: Spectra.

If the unaliased peak is picked, the peak box will automatically be shown on both the aliased and unaliased positions. Analysis distinguishes between aliased peaks and non-aliased peaks by using dashed peak boxes for the aliased peaks:

More about aliasing can be found here.