The compound TMS is used as a reference in this technique, which has proton and carbon-13 varieties.
A method used in this technique that uses 45, 90, and 135 degree decoupler pulses is known as distortionless enhancement by polarization transfer. In this technique, the relationship between a quantity symbolized J and dihedral angles is given by the Karplus equation. A commonly used solvent in this technique is deuterated chloroform. The compound TMS is used as a reference in this technique, which has proton and carbon-13 varieties. For 10 points, name this spectroscopic technique from organic chemistry that is used to determine the structure of molecules. 
A method used in this technique that uses 45, 90, and 135 degree decoupler pulses is known as distortionless enhancement by polarization transfer.
NMR spectroscopy [accept specific types; or nuclear magnetic resonance] 