Open Ien Issues of Active Noise Control Applications

Abstract

Interest in active noise control has grown 2. Multi Channel Systems significantly over the past decades, successful industrial applications include active control ofsound in headsets, in A multiple-channel acoustic ANC system is illustrated industrial ducts and in propeller aircrafts, to name a few.in Fig. 1 as an example of a general multiple-chaon el ANC To extend the upper limiting frequency and attenuation systems For tonal like noises, a narrow-band feed-forward zone of active noise control systems, one of the solution is multiple channel ANC system with a non-acoustic sensor to use a multiple channel active noise control (ANC) (tachometer, optical rpm sensor) can be used to generate system with several secondary sources and error sensors.the reference signal. For more complex noises (car cabin), Multi-channel ANC also has application to a wide variety a broad-band feed-forward multi channel ANC system is ofproblems in manufacturing, industrial operations, and used, employing J > 1 reference sensors to form the consumer products. In this paper recent developments in reference signal vector. ANC technology are reviewed and the technical problems Another kind of ANC system employs adaptive still standing in the way of widespread application are feedback, where the reference signals are internally discussed. Current research directions are outlined and the synthesized based on the secondary and error signals. The future ofthe discipline is examined. multiple channel ANC system generates K canceling signals to drive the corresponding secondary sources, and M error sensors are distributed over desired locations to measure the residual noise components [2].

Processor-efficient FFT Implementation Scheme for Active Noise Control Applications

“…Let the error e(n) which is generated at time instants n = 1, 2, 3, … , N-1, N, N+1, N+2,…, 2N-1, 2N, 2N+1,…, 3N-1, 3N,… be represented as e(1), e (2), …, e (N-1), e(N), e(N+1), e(N+2),…, e(2N-1), e(2N) , e(2N+1), e(2N+2), …, e(3N-1), e(3N),..., respectively.…”

“…Thus, 1 B corresponds to 4 real additions. In the case of 2 B , the twiddle factor is of the form / 4 N N w (= -j), which is again a trivial multiplication. As the multiplication of two complex numbers requires 4 real multiplications, the 3 B butterfly takes 8 real multiplications (4 each due of the presence of the twiddle factors 2 16 w and 6 16 w in Fig.…”

“…ANC has been gaining importance over the past few decades because of its wide range of applications, such as in head phones, duct of an air-conditioning system, exhaust and motor noise, interior of an elevator, car, etc., where there is a requirement to reduce unwanted noise levels [1,2]. As is evident from the literature, ANC can be implemented either in the time-domain (TD) or frequency-domain (FD).…”

Evaluating the Performance of Training Algorithms in Active Noise Control Using MLP Neural Network

“…The digital designs appeared in 1975 and 1978 by kido and chaplin [2]. Active noise control has several applications such as fans and pumps noise reduction, engine noise cancellation, control of aircraft cabin noise and reduction of car interior noise [1,3]. New applications of ANC have been introduced in [4].…”