The present contribution summarizes the efficiency of active flow control of the boundary layer of air around the hump. The synthetic jet generator with rectangular output part, i.e. slot, is actuated using a modulated signal. The modulated signal phase shift and its influence on the loss coefficient is investigated. The synthetic jet influences the character of the boundary layer and the size of the mixing area in a positive way. Decrease of the loss coefficient resulting from the change of the mixing size area (i.e. wake) is investigated. A velocity profile and a pressure profile were measured behind the hump by the CTA probe and the Kiel probe, respectively. Loss coefficients were obtained from total pressure measurements, each with a different measurement setup. These coefficients were compared with each other to show the benefits of the synthetic jet active flow control technique.