  We work in a model where all CP violating phenomena have a common source. CP
is spontaneously broken at a large scale $V$ through the phase of a complex
singlet scalar. An additional $SU(2)_L$ singlet vector-like down-type quark
relates this high scale CP violation to low energy. We quantitatively analyze
this model in the quark sector. We obtain the numerical values of the
parameters of the Lagrangian in the quark sector for a specific ansatz of the
$4\times4$ down-type quark mass matrix where the weak phase is generated
minimally. $Z \bar b b$ vertex will modify in presence of the extra vector-like
down-type quark. From the experimental lower bound of the partial decay width
$Z\to \bar b b$ we find out the lower bound of the additional down-type quark
mass. Tree level flavor changing neutral current appears in this model due to
the presence of the extra vector-like down-type quark. We give the range of
values of the mass splitting $\Delta m_{B_q}$ in $B^0_q-{\bar B}^0_q$ system
using SM box, $Z$ mediating tree level and $Z$ mediating one loop diagrams
together for both $q=d, s$. We find out the analytical expression for
$\Gamma_{12}^q$ in this model from standard box, $Z$ and Higgs mediated penguin
diagrams for $B^0_q-{\bar B}^0_q$ system, $q=d,s$. From this we numerically
evaluate the decay width difference $|\Delta\Gamma_{B_q}/\Gamma_{B_q}|$. We
also find out the numerical values of the CP asymmetry parameters $a_J$ and
$a_\pi$ for the decays $B^0_d\to J/\psi K_s$ and $B^0_d\to \pi^+ \pi^-$
respectively. We get the lower bound of the scale $V$ through the upper bound
of the strong CP phase.
