| 摘要 |
<p>An acoustic signature reduction system (101) for application typically on an aircraft (201). The acoustic signature reduction system uses a controller (107), power supply (105), and a thermo-acoustic tube (103) such as a Rijke tube or Sondhauss tube to generate a cancellation noise of equal amplitude and inverted to that of noise generated by rotor blades (207, 211) when rotating. Acoustic signature reduction system can use a damping valve (115) to make an intermittent cancellation sound to match the n/rev signature of the rotor blades with respect to a given reference location (401). The n/rev timing is different depending on the reference location therefore a cone of silence is created. A forced air unit (117) may also be used to modify the phase of the cancellation noise in order to move the cone of silence around the aircraft.</p> |
