BU – Buffers subroutine (requires 1D or Full version)
This subroutine allows display of multiple spectra, with chemical shifts aligned. The spectra do not need to have the same spectrometer frequency, sweep width and/or number of data points. Spectra can also be added and subtracted, but this requires the number of data points of the 2 spectra to be the same.
The subroutine works by placing spectra, or sections of spectra, into a series of "buffers", each displayed at a specified vertical position on the screen. The buffer spectra are displayed above the current spectrum such that the ppm scale is the same for all. The display of each is adjusted to compensate for different parameters.
The Buffers subroutine is entered by typing BU or from the Tools menu. The notation "Buffer" is displayed in the gray Status Bar at the bottom of the window. As with all subroutines, the <Enter> key will exit the routine. While in the Buffers subroutine, the displayed region of the current spectrum can be placed into a buffer using the subcommand A (or from the Edit menu). If an expanded region of the spectrum is displayed when the buffer is loaded, the buffer will contain only that region.
The buffers are numbered in the order in which they are added. The last buffer created is designated as the current buffer, and to indicate this, its text label is outlined. Other buffers can be made current by using the right and left arrow keys to move through the list of buffers. Several commands act on the current buffer, so be sure the desired buffer is made current before executing commands.
The current buffer can be deleted with the D command. All buffers can be cleared with the C command. Both commands are also available from the Edit menu.
Display of the buffer spectra outside of the buffers subroutine is turned on and off with subroutine commands S (show) and N (no-show), respectively. These commands are also available on the Edit menu.
While display of buffer spectra is enabled, text is also displayed as an identifier for the main spectrum (the current data file) so that all displayed data are labeled. The label for this spectrum is the Comment text.
The font used for the text labels can be set using the F command or from the Edit menu.
The color, text label, amplitude and vertical position of each buffer can be edited using the E command, also available from the Edit menu. This command displays the dialog box shown below. Display of the text label can be toggled on or off. It is also possible to set the background for the text label to be transparent, which may be preferable if the label overlaps part of the spectrum.
The buffers routine can be used to add or subtract 2 spectra. The spectra must have the same number of data points. Place the first spectrum into a buffer, then open the second spectrum. In the buffers routine, set the multiplying factor using the M command. To add them, the multiplier should be +1. To subtract them, M should be -1. Then use the + command to combine them. The sum (or difference) replaces the current spectrum.
- A — Add a buffer containing a copy of the current spectrum
C — clear all buffers
D — Delete current buffer
E — Edit parameters for current buffer
F — Set font for current buffer
M — Set multiplier for current buffer, for use in math functions
N — No-Show buffers after exiting subroutine
S — Show buffers after exiting subroutine
+ — Add current buffer to the current spectrum, which changes the current spectrum
- Right arrow key – advance to next buffer in the list
- Left arrow key – move to previous buffer in the list
> — Increase scale of current buffer by 10%
< — Decrease scale of current buffer by 10%
ENTER — exit buffers subroutine
Last updated: 11/8/06.