  We studied the Volovik effect on the NMR measurements of the two
unconventional superconducting (SC) states, the d-wave and $\pm$s-wave states.
We showed the generic field dependencies of the spin-lattice relaxation rate
$1/T_1$ and Knight shift $K$ at low temperature limit in the pure cases as:
$1/T_1 \propto H \log H$, $K \propto \sqrt{H}$ for the d-wave, and $1/T_1
\propto H$, $K \propto H$ for the $\pm$s-wave state, respectively. Performing
numerical calculations we showed that these generic power laws survive for the
good part of low field region with the realistic amount of impurities. We also
found that the Volovik effect acts as an equivalent pair breaker as the unitary
impurity scattering, hence induces the same temperature evolutions on $1/T_1$
and $K$, respectively, as the unitary impurities in both SC states. This
finding implies that the Volovik effect should always be taken into account for
the analysis of the NMR measurements in the mixed state.
