Aircraft jet engine including a system for reducing noise

The engine has a noise reducing system for reducing noise generated by ejection of gas stream from a nozzle. The system includes a duct connected in upstream to a recess (24) divided into a central chamber (54) and side chambers (56, 58). The duct opens in downstream at an outlet of the nozzle to eject fluid jet interacted with the ejected stream. A fluid jet pulsation unit (12) ejects the fluid jet at the outlet and/or modulates speed of the fluid jet by varying volume in the recess using piezoelectric deformable membranes (20, 22). The system balances static pressures between the chambers.