  In this work we have explored few tools in Quantum State Tomography for
Continuous Variable Systems. The concept of quantum states in phase space
representation is introduced in a simple manner by using a few statistical
concepts. Unlike most texts of Quantum information in which the Wigner function
for a single mode is often more used, in this text the multi-modes state Wigner
function is also approached. Our numerical investigations indicate that the
reconstructed method using back-projection add some error due the choice of
cutoff frequency, therefore it is necessary to use data post-processing, like
the semi-definite programs, which provides sufficient conditions correctly
estimate the state. Once the information about the state is recovered,
important features such as entanglement can also be investigated.
