We present the results obtained from analysis of two AstroSat observations high mass X-ray binary pulsar OAO 1657-415. The covered 0.681–0.818 and 0.808–0.968 phases $$\sim $$ 10.4 day orbital period system, in March July 2019, respectively. Despite being outside eclipsing regime, power density spectrum first observation lacks any signature pulsation or quasi-periodic oscillations. However, dur...