  The "Tapered Gridded Estimator" (TGE) is a novel way to directly estimate the
angular power spectrum from radio-interferometric visibility data that reduces
the computation by efficiently gridding the data, consistently removes the
noise bias, and suppresses the foreground contamination to a large extent by
tapering the primary beam response through an appropriate convolution in the
visibility domain. Here we demonstrate the effectiveness of TGE in recovering
the diffuse emission power spectrum through numerical simulations. We present
details of the simulation used to generate low frequency visibility data for
sky model with extragalactic compact radio sources and diffuse Galactic
synchrotron emission. We then use different imaging strategies to identify the
most effective option of point source subtraction and to study the underlying
diffuse emission. Finally, we apply TGE to the residual data to measure the
angular power spectrum, and assess the impact of incomplete point source
subtraction in recovering the input power spectrum $C_{\ell}$ of the
synchrotron emission. This estimator is found to successfully recovers the
$C_{\ell}$ of input model from the residual visibility data. These results are
relevant for measuring the diffuse emission like the Galactic synchrotron
emission. It is also an important step towards characterizing and removing both
diffuse and compact foreground emission in order to detect the redshifted $21\,
{\rm cm}$ signal from the Epoch of Reionization.
