  We present a detailed study of pion and rho mass, decay constants and quark
mass in Lattice QCD with two flavors of dynamical quarks. We use Wilson gauge
and fermion action at $\beta=5.6$ on $ 16^3 \times 32 $ lattice at eight values
of the Wilson hopping parameter in the range 0.156 - 0.158. We perform a
detailed investigation of the effect of gaussian smearing on both source and
sink. We determine the optimum smearing parameter for various correlators for
each value of the Wilson hopping parameter. The effects of smearing on
observables are compared with those measured using local operators. We also
investigate systematic effects in the extraction of masses and decay constants
using different types of correlation functions for pion observables. We make
interesting observations regarding chiral extrapolations and finite volume
effects of different operators.
