  Stellar companion of a black hole orbiting in an eccentric orbit will
experience modulating tidal force with a periodicity same as that of the
orbital period. This, in turn, would modulate accretion rates, and the seed
photon flux which are inverse Comptonized to produce harder X-rays. By
analyzing complete all sky monitor (ASM) data (1.5-12 keV) of RXTE and all sky
survey data (15-50 keV) of Swift/BAT we discover this periodicity in several
objects. We also estimate eccentricities from the RMS power of the peak around
quasi-orbital periods (QOP). Our method provides an independent way to obtain
time periods and eccentricities of such compact binaries.
