The Pulse Program Parameters Window

This panel lists all parameters necessary for running the pulse sequence. Those parameters not defined in the pulse sequence (via arithmetic expressions) and not assigned by default (see below) are marked as NaN. In order to be able to run the simulation, you must substitue all NaN's by numbers or expressions.
Note: A new panel is generated automatically every time Xlate is executed, hence you will have to open this panel and re-enter pulse program parameters.
Brief Comments:

  1. Entering Parameter Values:You can input numbers directly, or you can use arithmetic expressions (no quotation marks!), relating undefined parameters to those already defined. For example, typing
    1e-5 or 10u or p1 or ex.p90c(1)
    in the box for p0 will produce the same effect, i.e. set p0 to 10 microseconds.
  2. Time Units: The program recognizes time units in a similar way to XWINNMR, i.e. s=seconds, m=milliseconds, u=microseconds. Note: If no unit is specified, when entering a number for a delay or pulse, it will be interpreted as in seconds.
  3. Default Values: The following parameters are assigned default values (you can change these at any time by typing in the desired values):
  4. "Standard" Gradient and RF Pulse Shapes Available:
  5. User-Defined Gradient and/or RF Pulse Shapes: You can create your own shape using the Shape Generator -- a graphical tool for making user-designed shaped pulses. You can also create your own shape using matlab or any text editor and save it as an ascii file containing a column or a row of numbers (on a scale from 0 to 1) representing the desired pulse shape. In order to be recognized by NMR, these data should be saved as a file with extension 'shp' (e.g. myshape.shp) in a directory included in matlab path (recommended default directory: vs_shapes).
  6. How to Enter Shape Names: If a shaped RF pulse or a pulsed field gradient is used in the pulse program, xlator will assign it a default shape ('sine'). If you want to use a different shape, type it in the corresponding box in the Program Parameters Window. The shape name must be encompassed by single apostrophes (as in the example here)! Shape name recognition tool in VNMR is case-insensitive. If the shape name has been recognized, VNMR will repeat the selected shape to the right of the shape-name box. Otherwise, if the shape you typed in is neither standard recognized shape (listed above) nor a legitimate file name (don't type the .shp extension!), you will see a message 'not found' to the right of the box for shaped pulse name. Check the right name and re-enter it.
    Note: The shape name recognition tool in VNMR is case-insensitive: e.g. 'SINE', 'Sine', 'siNE' etc will all be recognized as 'sine'. Please keep in mind, however, that Matlab file search tool under Unix/Linux could be case sensitive.

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    Page designed by David Fushman & Peter Nicholas. Modified 11/29/2002.