Locking in vnmr

From NMR Wiki

Figure 1. Default view of vnmr Acqi window. Buttons "Insert/Inject" control position of sample. Button "Close" will close the window. Other buttons will allow access to different functions of interactive acquisition.

in vnmr command line type 'acqi' or click 'Acqi' button. A window as shown below will open.

Now click "Lock" button. The window will change into something like this:

The curve that you see in the window is an FID (free induction decay) of lock nucleus (most often-deuterium).