NIH-XPLOR
From NMR Wiki
Xplor calculates structures conforming experimental NMR restraints such as NOE, RDC, scalar couplings, etc.
XPLOR system is complex and hard to learn from scratch, so a good tutorial would be very desirable. There are many tools that manipulate XPLOR restraint tables. Links to them should be posted here as well.
Official NIH-XPLOR Documentation Site
References
Schwieters, C.D., Kuszewski, J.J., Tjandra, N., Marius Clore, G.. The Xplor-NIH NMR molecular structure determination package
