| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an active muffler capable of eliminating a high frequency component of the noise. SOLUTION: In this active muffler 10 having a first noise detecting means, a means mounted at a downstream side of a duct and outputting a muffling signal, an operating means for calculating the muffling signal of a phase opposite to that of a noise signal detected by the first noise detecting means, and a second noise detecting means mounted at a downstream side with respect to the output means, in the duct 1 mounted at a noise side, a passive muffler 11 is mounted on the duct at an upstream side with respect to the output means, the passive muffler is composed of several stages, and a part closest to the output means is the muffler having a resonance structure.</p> |
