Closed loop control system for active noise reduction and method for active noise reduction
First Claim
1. A closed loop control system for active noise reduction, comprising:
- a loudspeaker for outputting sound;
an adding device that features a first and a second input and to which the loudspeaker is connected;
a feedforward control witha first microphone for receiving noise interference, anda first control network with at least one filter for forming a first controlled variable, wherein the first control network is coupled to the first microphone on its input side and is coupled to the adding device on its output side in order to supply the first controlled variable;
a feedback control witha second microphone for receiving a sound being output by the loudspeaker, anda second control network with at least one filter for forming a second controlled variable, wherein the second control network is coupled to the second microphone on its input side and is coupled to the adding device on its output side,wherein the feedback control is tuned to a noise reduction based on a first acoustic ratio, the feedforward control is tuned to a noise reduction based on a second acoustic ratio, and the second control network is designed for at least partially compensating the first controlled variable when the current acoustic ratios change in the direction of the first acoustic ratio, andwherein the tuning of the feedforward control and the feedback control is unchangeable at least during the operation of the control system.
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Abstract
The invention relates to a closed loop control system for active noise reduction, comprising a speaker and an adding device connected to the speaker. A feedforward control and a feedback control each comprise a microphone for recording noise interference or for recording a sound output by the speaker. Control networks for forming a corresponding control parameter are coupled to the corresponding microphones and are connected to the adding device at the output side thereof. According to the invention, the feedback control for noise reduction is adapted on the basis of a first acoustic ratio and the feedforward control for noise reduction is adapted on the basis of a second acoustic ratio. The control network of the feedback control is designed to at least partially compensate for the control parameter of the feedforward control when current acoustic ratios change in the direction of the first acoustic ratio.
21 Citations
20 Claims
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1. A closed loop control system for active noise reduction, comprising:
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a loudspeaker for outputting sound; an adding device that features a first and a second input and to which the loudspeaker is connected; a feedforward control with a first microphone for receiving noise interference, and a first control network with at least one filter for forming a first controlled variable, wherein the first control network is coupled to the first microphone on its input side and is coupled to the adding device on its output side in order to supply the first controlled variable; a feedback control with a second microphone for receiving a sound being output by the loudspeaker, and a second control network with at least one filter for forming a second controlled variable, wherein the second control network is coupled to the second microphone on its input side and is coupled to the adding device on its output side, wherein the feedback control is tuned to a noise reduction based on a first acoustic ratio, the feedforward control is tuned to a noise reduction based on a second acoustic ratio, and the second control network is designed for at least partially compensating the first controlled variable when the current acoustic ratios change in the direction of the first acoustic ratio, and wherein the tuning of the feedforward control and the feedback control is unchangeable at least during the operation of the control system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for active noise reduction for a loudspeaker that serves for the output of sound, the method comprising:
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making available a feedback control for noise reduction that is tuned to a first acoustic ratio; making available a feedforward control for noise reduction that is tuned to a second acoustic ratio; and compensating a controlled variable of the feedforward control with a controlled variable of the feedback control when current acoustic ratios change in the direction of the first acoustic ratio, wherein the tuning of the feedforward control and the feedback control cannot be changed at least during the control operation. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification