  The conductance through a local nuclear spin precessing in a magnetic field
is studied by using the equations-of-motion approach. The characteristics of
the conductance is determined by the tunneling matrix and the position of
equilibrium chemical potential. We find that the spin flip coupling between the
electrons on the spin site and the leads produces the conductance oscillation.
When the spin is precessing in the magnetic field at Larmor frequency
($\omega_{L}$), the conductance develops the oscillation with the frequency of
both $\omega_{L}$ and 2$\omega_{L}$ components, the relative spectrum weight of
which can be tuned by the chemical potential and the spin flip coupling.
