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Calibration Window

This window displays the measured and expected peak positions while calibrating an overlay. See Calibrating Spectra for how to use this. The combination box on top selects the overlay that is being worked on.

The grid contains the following items:
Measured The peak position, normally entered by click and drag on the experimental spectrum
Actual The true peak position, typically entered by click and drag on the calibration spectrum after pressing the assign button
Residual Observed-Calculated from last fit
Std Dev
 Estimated relative standard deviation of the peak position. This is used to derive the weights in the least squares fit. Only the relative values matter, so typical usage might be to use 1 for most measurements and larger values, say 3 or 10, for less accurate measurements. A negative or zero standard deviation is used to flag a point to be excluded from the fit.

Controls
Select the spectrum to calibrate
Assign current peak; the "Actual" cell of the current row will turn red, and will be filled in by the position of the next peak you measure.
Fit to given order of polynomial
Undo last fit
Copy selected lines to clipboard
Delete selected lines
Open custom fit dialog - allows the use of any function, not just a polynomial
Delete unassigned lines
Other operations - shows an additional menu, described below.
Select order of polynomial for calibration fit
Displays root mean square error of current fit

Other... Operations

Copy Frequency To... Copy Frequency scale to another overlay; this process assumes that the two overlays have exactly the same x axis (i.e. the ith point on each overlay corresponds to the same frequency). Any x axis on the target overlay is thus discarded. (Contrast with "Apply Calibration To" below.) This is intended for use on spectra recorded simultaneously.
Apply Calibration To... Apply calibration curve to other overlay. This applies the calibration function of the current overlay to the x axis of the target overlay, so there is no requirement for the frequency scales to match. (c.f. "Copy Frequency to" above.) This is intended to transfer a calibration curve of, for example, voltage to frequency, from one spectrum to another.
Clear Delete all lines
Set Range Set approximate range
Reset Reset calibration to default, i.e. FrequencyScale=1, FrequencyOffset=0
Etalon Given two approximately spaced peaks, find all the other
Spline... Generate cubic spline though calibration points. See Using Etalons for some comments on usage.