Active noise control system

A technology of noise reduction and detection device, which is applied in the fields of noise reduction device, transportation and packaging, active noise control, etc., can solve the problems of low noise reduction effect and so on

Inactive Publication Date: 2005-02-02
PANASONIC CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When there is a difference between the noise level of the noise suppressing part and the noise level at the position of the passenger's ear, there is also a problem of creating an overcompensation state in which the noise reduction effect is small at the position of the passenger's ear.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Components that are the same as those of the existing active noise reduction devices shown in the prior art are given the same reference numerals. The present invention will be described, for example, when it is installed in a vehicle or the like to reduce noise generated in a vehicle cabin due to engine vibration.

[0029] figure 1 The active noise reduction device according to Embodiment 1 is shown as a block diagram. figure 1 Among them, the engine 21 is a noise source that generates noise that becomes a problem, and this active noise reduction device operates to reduce the periodic noise radiated from the engine 21 .

[0030]An engine pulse, which is an electrical signal synchronized with the rotation of the engine 21 , is input to the waveform shaper 1 , and waveform shaping is performed while filtering superimposed noise and the like. As this engine pulse, it i...

Embodiment approach 2

[0071] In Embodiment 1 above, it has been explained that the signal obtained by adding the correction signal h to the output signal (error signal e) of the microphone 24 is used in the adaptive control algorithm for updating the filter coefficients W0 and W1 of the adaptive notch filter 4, Therefore, while suppressing overcompensation, the control stability is improved. In Embodiment 2, a method of further adjusting the suppression amount of overcompensation will be described.

[0072] Figure 7 The configuration of the active noise reduction device according to Embodiment 2 is shown as a block diagram. Components that are the same as those of the noise reduction device shown in the above-mentioned embodiments are denoted by the same reference numerals.

[0073] Figure 7 in, with figure 1 The only difference is that a coefficient multiplier 35 is added to the correction signal generator. Here, the correction signal h which is the output signal of the adder 33 is input t...

Embodiment approach 3

[0087] Figure 9 The active noise reduction device according to Embodiment 3 is shown as a block diagram along with its components. The same reference numerals are attached to the same constituent elements as those of the active noise reduction device shown in Embodiment 1 or Embodiment 2 above.

[0088] Figure 9 in, with Figure 7 The only difference is that the output control unit 36 ​​is added to the correction signal generator. The output signal Kh of the coefficient multiplier 35 is now input to the output control section 36 . This output control unit 36 ​​has a memory area for storing the value of the filter coefficient W0 of the first one-tap adaptive filter 5 every time it is updated from the past predetermined time (for example, before the filter coefficient is updated 20 times) to the present, and calculates its change. cumulative value of the quantity. It also has a storage area for storing the value of the filter coefficient W1 of the second single-tap adapti...

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PUM

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Abstract

An active noise control system is provided which cancels a noise using a sound radiated from a speaker driven by an output from an adaptive notch filter. The system employs output signals from an adder or simulation cosine-wave and sine-wave signals, an error signal or an output signal from a microphone, and a compensated signal from the adder or a signal available for acoustically transferring an output from the adaptive notch filter to the microphone in accordance with initial transfer characteristics to update the filter coefficient of the adaptive notch filter. This configuration allows the system to operate with stability even when the acoustic transfer characteristics vary with time or under circumstances where there exists a significant amount of incoming external noises. The system also prevents overcompensation for a noise at the ears of a passenger in a vehicle, thereby proving an ideal noise reduction effect.

Description

technical field [0001] The present invention relates to an active noise reduction device, which interferes with the annoying engine howling sound generated in the vehicle compartment with the rotation of the engine, so as to reduce the engine howling sound. Background technique [0002] Engine howling is the radiation sound generated by the vibration force generated by the rotation of the engine, which is transmitted to the body and causes resonance in the compartment of the enclosed space under certain conditions, so it has a significant periodicity that is synchronous with the engine speed. [0003] A method of performing feedforward adaptive control using an adaptive notch filter is known as an existing active noise reduction device for reducing such annoying engine noise (for example, refer to JP-A-2000-99037). Figure 10 The composition of the conventional active noise reduction device described in JP-A-2000-99037 is shown. [0004] Figure 10 Among them, processing is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B60R11/02G10K11/178
CPCG10K2210/101G10K2210/3012G10K2210/128G10K2210/511G10K11/1784G10K11/17835G10K11/17854G10K11/17883
Inventor 中村由男大西将秀井上敏郎高桥彰
Owner PANASONIC CORP
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