Secondary channel offline identification method and system for headphone active noise control

A technology of active noise control and secondary channel, which is applied in earphones to reduce environmental noise, earpieces/earphone accessories, microphones, etc. It can solve problems such as complex identification algorithms and unstable convergence speed, achieve good noise reduction effects, and be easy to use for hardware The effect of realization and simple structure

Active Publication Date: 2019-02-22
SICHUAN CHANGHONG ELECTRIC CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide an off-line identification method for the secondary channel of earphone active noise control, which is used to solve the problems in the prior art that the convergence factor is adjusted by fixed compensation or empirical formula, the identification algorithm is complicated, and the convergence speed is unstable.

Method used

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  • Secondary channel offline identification method and system for headphone active noise control
  • Secondary channel offline identification method and system for headphone active noise control
  • Secondary channel offline identification method and system for headphone active noise control

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] The established ANC system secondary channel transfer function model is expressed as The approximate model Sh(z) of the transfer function of the secondary channel function is obtained through actual measurement, specifically:

[0037] Step (1): Collect the amplitude-frequency response and phase-frequency response data of each frequency pulse transmitted through the secondary channel, and store it in a variable The parameters a and b of the initialization transfer function are stored in Set the threshold tol, and assign the initial value of variable l to 1;

[0038] Step (2): Calculate the error between the estimated value and the real value under the initial parameters:

[0039]

[0040] Compute the Jacobian matrix:

[0041]

[0042] Step (3): Calculate the sum of squared errors and Among them, the intermediate variable

[0043] Step (4): According to the Gauss-Newton iteration method, it can be known that the iteration variable is initialized

[0...

Embodiment 2

[0051] to combine figure 1 and figure 2 As shown, the main channel specifically refers to the channel through which the external noise signal passes through the first D / A converter, the first reconstruction filter, and the first power amplifier to output sound waves from the main speaker of the earphone; the specific path of the secondary channel is from the secondary The physical path between the loudspeaker and the error sensor, which physically includes the second D / A converter, the second reconstruction filter, the second power amplifier, the secondary loudspeaker, and the connection between the secondary loudspeaker and the error microphone Physical channels, sound fields, electro-acoustic devices, electronic circuits, etc. Channels can be regarded as scene-dependent time-invariant systems when performing offline modeling of secondary channels. Assuming that the transfer function of the secondary channel S(z) is H(z), the offline identification of the secondary channel...

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Abstract

The invention discloses a secondary channel offline identification method for headphone active noise control. The method comprises the following steps: step S100, establishing an ANC system secondarychannel transfer function model S(z) as shown in description; step S200, determining a parameter of a transfer function model S(z); and step S300, substituting the parameter into an inverse filter ofthe S(z), performing LMS self-adaptive filter to obtain noise elimination sound wave produced by a secondary loudspeaker and opposite to the same phase of a main loudspeaker amplitude. By adopting anapproximate model of the secondary channel is obtained through real measurement, and then a method of approximating the actual secondary channel mode is performed to obtain a parameter of an actual secondary channel transfer function; therefore, an offline modeling method is adopted, the structure is simple, the hardware realization is easy, and the method is simple and feasible. The parameter issubstituted into the inverse filter of the S(z) to perform LMS self-adaptive filtering to obtain the noise elimination sound wave produced by a secondary loudspeaker and opposite to the same phase ofa main loudspeaker amplitude, thereby obtaining good noise reduction effect.

Description

technical field [0001] The invention relates to the technical field of noise reduction earphones, in particular to an off-line identification method for a secondary channel of active noise control of earphones. Background technique [0002] With the improvement of living standards, people's requirements for the quality of music enjoyment are getting higher and higher, and the problem of noise in life and travel has attracted widespread attention all over the world. Because passive noise reduction technology is difficult to filter out low-frequency noise, active noise control is effective and efficient in dealing with various noisy scenes. Therefore, the automatic noise control system (ANC) designed according to the principle of active noise control has been widely used in noise reduction headphones, automotive electronics and aerospace fields. The secondary path refers to the channel from the secondary sound source to the error sensor. Accurate modeling and identification o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04R1/10
CPCH04R1/1083H04R2201/10
Inventor 韩大强陈龙
Owner SICHUAN CHANGHONG ELECTRIC CO LTD
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