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A Design Method of Analog Feedback Active Noise Cancelling Headphones

A technology of noise reduction earphones and design methods, which is applied in earpiece/earphone accessories, computing, special data processing applications, etc., can solve the problems that physics cannot be realized, and analog circuit units cannot realize the second-order stable system transfer function, etc., and achieve low sensitivity Features, good physical realizability, guaranteed effect of noise reduction performance

Active Publication Date: 2016-08-17
NANJING UNIV
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Problems solved by technology

Furthermore, a given analog circuit unit cannot realize a second-order stable system transfer function with arbitrary pole-zero positions
If the zero-pole position of the transfer function of the second-order stable system is improper, the actual circuit parameters of the specified unit circuit will be negative, which is physically impossible

Method used

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  • A Design Method of Analog Feedback Active Noise Cancelling Headphones
  • A Design Method of Analog Feedback Active Noise Cancelling Headphones
  • A Design Method of Analog Feedback Active Noise Cancelling Headphones

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Embodiment Construction

[0031] The feature of the analog feedback active noise reduction earphone design method proposed by the present invention is: based on H ∞ The frequency characteristics of the controller are optimized by technology synthesis; the optimized frequency characteristics of the controller are realized by the digital filter first, and then the frequency characteristics of the digital filter are fitted to the low-order continuous domain transfer function; the obtained low-order is realized by the generalized second-order GIC circuit Continuous domain transfer function. The design method will be described in detail below by taking the realization of an analog feedback active earphone with a maximum noise reduction of 18dB in the frequency band below 1000 Hz as an example.

[0032] (1) Wear the earphone on the artificial head, and test the frequency characteristics of the secondary path as attached image 3As shown, the nominal path is the secondary path when the earphone is worn in th...

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Abstract

The invention discloses a design method of an analog feedback active noise reduction earphone, which is characterized in that: based on H ∞ The frequency characteristics of the controller are optimized by technology synthesis; the optimized frequency characteristics of the controller are realized by the digital filter first, and then the frequency characteristics of the digital filter are fitted to a low-order continuous domain transfer function; the obtained low-order Continuous domain transfer function. Its remarkable advantages are: (1) based on H ∞ The frequency characteristics of the controller optimized by technology synthesis ensure the optimization of noise reduction performance and the robustness of the system; (2) the digital filter first realizes the optimized frequency characteristics of the controller, and then fits the frequency characteristics of the digital filter to low-order The continuous domain transfer function of the controller guarantees the minimum phase characteristics of the controller; (3) the application of the generalized second-order GIC circuit can realize the second-order stable system transfer function of any zero-pole position, and has low sensitivity characteristics, and the physical realization is good.

Description

1. Technical field [0001] The invention relates to a control design method of a feedback active noise control system, and mainly provides an analog feedback design method for an active noise reduction earphone. 2. Background technology [0002] Active earphones are used as a hearing protection device, and its structure is as follows: figure 1 As shown, it consists of a microphone, a circuit (including a preamplifier circuit, a control circuit and a power amplifier circuit), and a secondary source (speaker). Its noise reduction design is mostly realized based on feedback technology. Usually, given the design goal, a certain optimization design method is applied to obtain the optimized frequency characteristics of the controller, and digital feedback or analog feedback is used to realize it. [0003] Digital feedback has the advantages of high flexibility and easy implementation. Rafaely et al. Applied H 2 performance criteria and H ∞ A digital feedback controller was desi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/50H04R1/10
Inventor 张丽敏邹海山卢晶邱小军
Owner NANJING UNIV
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