Passive noise reduction is a classical approach to attenuate industrial noise. But Active noise cancellation has several advantages over the passive noise cancellation.
Such a system offers a better low frequency performance with a smaller and ligh...
Passive noise reduction is a classical approach to attenuate industrial noise. But Active noise cancellation has several advantages over the passive noise cancellation.
Such a system offers a better low frequency performance with a smaller and lighter system. This paper presents an active closed loop control system which consists of a controller for inverting and compensating the phase delay, a microphone for picking up the external noise, and a loudspeaker for radiating the acoustic anti-phase signal to reduce the external noise.
The noise in the phase delay covered from 0 to 180˚tends to be reduced. The degree of noise cancellation obtainable with this system reaches value 15dB.