Active noise cancellation system
AssigneeHelmut-Schmidt-Universitaet Universitaet der Bundeswehr Hamburg
InventorsPiero Rivera Benois, Udo Zoelzer
Life of this patent
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Abstract
An active noise cancellation system for reducing unwanted noise in a target area by attenuating a disturbance noise signal (d(n)), which is the remaining noise in the target area originated from an ambient noise signal (x(n)) present in the vicinity of the target area that is transferred to the target area via a main path described by a transfer function P(z)), the active noise cancellation system including a processing unit that implements an ANC-controller which is configured to provide a control signal (y′(n)) for controlling a speaker in the target area in order to generate an acoustic signal (y(n)) that destructively overlaps with the disturbance noise signal (d(n)) and thereby attenuates the same.
Claims15
An active noise cancellation system (300, 400, 500) for reducing unwanted noise in a target area (22) by attenuating a disturbance noise signal (d(n)), which is the remaining noise in the target area (22) originated from an ambient noise signal (x(n)) present in the vicinity of the target area (22) that is transferred to the target area via a main path described by a transfer function (P(z)), the active noise cancellation system (300, 400, 500) comprising a processing unit that implements an ANC-controller (310, 410, 510) which is configured to provide a control signal (y′(n)) for controlling a speaker (20) in the target area (22) in order to generate an acoustic signal (y(n)) that destructively overlaps with the disturbance noise signal (d(n)) and thereby attenuates the same, wherein the control signal (y′(n)) is transferred into the acoustic signal (y(n)) via a secondary path described by a transfer function (S(z)), and wherein the ANC-controller provides a system transfer function (H(z)), which minimizes a residual error signal (e(n)), wherein the residual error signal (e(n)) represents the difference between the acoustic signal (y(n)) and the disturbance noise signal (d(n)) after a destructive overlap of the same, wherein the ANC-controller (310, 410, 510) comprises a control structure which consist of an Internal Model Control (IMC) feedback control structure (IMC control structure) comprising an IMC-controller (Wimc(z)) and a secondary path estimate filter described by a transfer function (Ŝ(z)), a Minimum Variance Control (MVC) feedback control structure (MVC control structure) comprising a MVC-controller (Wmvc(z)) and a feedforward (FF) control structure (FF control structure) comprising a FF-controller (Wff(z)), and wherein the IMC control structure, the MVC control structure and the FF control structure are interconnected and combined to form a common multi-hybrid control system.
An active noise cancellation system (200) for reducing unwanted noise in a target area (22) by attenuating a disturbance noise signal (d(n)), which is the remaining noise in the target area (22) originated from an ambient noise signal (x(n)) present in the vicinity of the target area (22) that is transferred to the target area (22) via a main path described by a transfer function (P(z)), the active noise cancellation system (200) comprising a processing unit that implements an ANC-controller (210) which is configured to provide a control signal (y′(n)) for controlling a speaker in the target area (22) in order to generate an acoustic signal (y(n)) that destructively overlaps with the disturbance noise signal (d(n)) and thereby attenuates the same, wherein the control signal (y′(n)) is transferred into the acoustic signal (y(n)) via a secondary path described by a transfer function (S(z)), and wherein the ANC-controller provides a system transfer function (H(z)), which minimizes a residual error signal (e(n)), wherein the residual error signal (e(n)) represents the difference between the acoustic signal (y(n)) and the disturbance noise signal (d(n)) after a destructive overlap of the same, wherein the ANC-controller (210) comprises a control structure which consist of at least two Internal Model Control (IMC) feedback control structures (IMC control structures), each comprising an IMC-controller (Wimc(z)) and a secondary path estimate filter described by a transfer function (Ŝ(z)), and wherein the IMC control structures are interconnected and combined to form a common multi-stage control system.
An active noise cancellation system (100) for reducing unwanted noise in a target area (22) by attenuating a disturbance noise signal (d(n)), which is the remaining noise in the target area (22) originated from an ambient noise signal (x(n)) present in the vicinity of the target area (22) that is transferred to the target area (22) via a main path described by a transfer function (P(z)), the active noise cancellation system (100) comprising a processing unit that implements an ANC-controller (110) which is configured to provide a control signal (y′(n)) for controlling a speaker in the target area (22) in order to generate an acoustic signal (y(n)) that destructively overlaps with the disturbance noise signal (d(n)) and thereby attenuates the same, wherein the control signal (y′(n)) is transferred into the acoustic signal (y(n)) via a secondary path described by a transfer function (S(z)), and wherein the ANC-controller (110) provides a system transfer function (H(z)), which minimizes a residual error signal (e(n)), wherein the residual error signal (e(n)) represents the difference between the acoustic signal (y(n)) and the disturbance noise signal (d(n)) after a destructive overlap of the same, wherein the ANC-controller (110) comprises a control structure which consist of at least two Minimum Variance Control (MVC) feedback control structures, each comprising a MVC-controller (Wmvc(z)) and a secondary path estimate filter described by a transfer function (Ŝ(z)), and wherein the MVC control structures are interconnected and combined to form a common multi-stage control system.
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