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Pulse noise active control method based on logarithm conversion

A technology of impulse noise and logarithmic transformation, applied in the direction of impedance network, adaptive network, electrical components, etc., can solve the problems that are not suitable for impulse noise active control, etc., and achieve practicality, good robustness, and good noise attenuation performance Effect

Inactive Publication Date: 2010-07-28
NANJING UNIV
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Problems solved by technology

Therefore, traditional active noise control methods based on second-order moments (mean square error), such as Filtered-x Least Mean Square (FxLMS), are not suitable for active control of impulse noise

Method used

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  • Pulse noise active control method based on logarithm conversion
  • Pulse noise active control method based on logarithm conversion
  • Pulse noise active control method based on logarithm conversion

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Embodiment Construction

[0022] The present invention will be described in detail below with a numerical simulation experiment of single-channel feedforward impulse noise control.

[0023] 1. System configuration

[0024] figure 2 is a block diagram of a logarithmic transform-based single-channel feed-forward active noise control system. It consists of a reference microphone for obtaining a reference signal x(n), an error microphone for obtaining an error signal e(n), and a secondary sound source for generating a secondary signal y(n) to cancel the main noise d(n) . Here x'(n) is the estimated value of the reference signal x(n) passing through the secondary channel S(z) After filtering, W(z) is an adaptive filter.

[0025] 2. Experimental conditions

[0026] The orders of the finite impulse response filter (FIR) of the main channel P(z) and the secondary channel S(z) used in the experiment are 800 and 250 respectively, and their frequency responses are as follows: image 3 As shown, here we se...

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Abstract

The invention discloses a self-adaptation filtering method for pulse noise active control. In the method, a mean square value of error signal logarithm conversion is taken as a cost function and a coefficient of a self-adaptation wave filter is regulated by minimizing the cost function. The method comprises the following steps of: firstly, initializing the coefficient W (n) of the self-adaptation wave filter; secondly, obtaining error e (n) between self-adaptation wave filter output and desired signals; and thirdly, if the absolute value of e (n) is no more than 1, not updating the coefficient of the self-adaptation wave filter; and if the absolute value of e (n) is bigger than 1, updating the coefficient of the self-adaptation wave filter, wherein n is a time serial number, mu is a step length factor, x'(n) is reference signals after secondary channel model wave filtering, and sign [e(n)] is a sign function. The method has favorable noise inhibition capability and robustness to pulse noises without needing the prior acknowledge of the pulse noise and without needing to estimate characteristic parameters of the pulse noise, thereby having great practical value.

Description

1. Technical field [0001] The invention relates to an active control method of impulse noise, in particular to a feedforward active control adaptive filtering method of impulse noise. 2. Background technology [0002] Impulse noise is a widespread noise signal, and its probability model is usually described by a non-Gaussian α-stable distribution. The smaller the α, the stronger the impulsiveness. An important property of the non-Gaussian α-stable distribution is that its p-order statistical moment exists only when 0<p<α, that is, the second-order statistic of the impulse noise does not exist (it tends to infinity). Therefore, traditional active noise control methods based on second-order moments (mean square error), such as Filtered-x Least Mean Square (FxLMS), are not suitable for active control of impulse noise. Several scholars have found that in an impulsive noise environment, FxLMS will encounter stability problems such as algorithm non-convergence, and have pro...

Claims

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Application Information

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IPC IPC(8): H03H21/00
Inventor 吴礼福邱小军
Owner NANJING UNIV
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