The 90º 13C decoupler pulse using a shaped pulse can be calibrated from the high-power 90º 13C decoupler pulse calibration parameter set-up. Proceed as follows:

Change the pulse program to decp90sp

Define the desired pulse shape in spnam2

Set o2 on the selected resonance

Define the pulse duration p13

Reach the nulling signal intensity by varying the sp2 power level