US 5,991,418 AGranted

Off-line path modeling circuitry and method for off-line feedback path modeling and off-line secondary path modeling

AssigneeTexas Instruments Incorporated

InventorSen M. Kuo

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Abstract

An off-line modeling system (50) is provided for modeling a feedback path and a secondary path by calculating feedback neutralization filter taps and secondary path compensation filter taps. The off-line modeling system (50) includes a reference sensor (16), a secondary source (18), an error sensor (20), and an off-line modeling circuitry (10). The reference sensor (16) receives a noise signal and a feedback signal (22) and generates a primary signal x(n) in response. The secondary source (18) receives a modeling signal v(n) and provides the modeling signal v(n) to the feedback path and the secondary path. The error sensor (20) receives a residual signal generates an error signal e(n). The off-line modeling circuitry (10) receives the primary signal x(n) and the error signal e(n) and generates the modeling signal v(n) while modeling the feedback path and the secondary path.

Claims31

Dependent claims

An off-line modeling system for modeling a feedback path and a secondary path, the off-line modeling system comprising:

a reference sensor operable to receive a noise signal and a feedback signal and to generate a primary signal in response;
a secondary source operable to receive a modeling signal and to provide the modeling signal through the feedback path and the secondary path;
an error sensor operable to receive a residual signal and to generate an error signal in response;
and
an off-line modeling circuitry for modeling the feedback path and the secondary path including:
a modeling signal generator operable to generate the modeling signal,
a feedback path signal discrimination circuitry operable to receive the primary signal and to generate a modified modeling feedback signal, said feedback path signal discrimination circuitry including:
a decorrelation delay unit operable to delay the primary signal and to generate a delayed output signal that corresponds to a delayed primary signal,
an adaptive discrimination filter operable to receive the delayed output signal and the modified modeling feedback signal and to filter the delayed output signal to generate a predicted noise signal, and
a first summing junction operable to subtract the predicted noise signal from the primary signal to generate the modified modeling feedback signal,
a feedback path modeling adaptive filter operable to receive the modeling signal and a feedback path modeling error signal and to filter the modeling signal to generate a first output signal, the feedback path modeling adaptive filter operable to calculate feedback neutralization filter taps,
a second summing junction operable to subtract the first output signal from the modified modeling feedback signal to generate the feedback path modeling error signal which is provided to a first adaptive algorithm used by the feedback path modeling adaptive filter,
a secondary path signal discrimination circuitry operable to receive the error signal and to generate a modified modeling secondary path signal,
a secondary path modeling adaptive filter operable to receive the modeling signal and a secondary path modeling error signal and to filter the modeling signal to generate a second output signal, the secondary path modeling adaptive filter operable to calculate secondary path compensation filter taps, and
a third summing junction operable to subtract the second output signal from the modified modeling secondary path signal to generate the secondary path modeling error signal which is provided to a second adaptive algorithm used by the secondary path modeling adaptive filter.

12 more elements

An off-line modeling circuitry for modeling the feedback path and the secondary path of an active noise control system, the off-line modeling circuitry comprising:

a modeling signal generator operable to generate the modeling signal;
a feedback path signal discrimination circuitry operable to receive a primary signal and to generate a modified modeling feedback signal, said feedback path signal discrimination circuitry including:
a decorrelation delay unit operable to delay the primary signal and to generate a delayed output signal that corresponds to a delayed primary signal,
an adaptive discrimination filter operable to receive the delayed output signal and the modified modeling feedback signal and to filter the delayed output signal to generate a predicted noise signal, and
a first summing junction operable to subtract the predicted noise signal from the primary signal to generate the modified modeling feedback signal;
a feedback path modeling adaptive filter operable to receive the modeling signal and a feedback path modeling error signal and to filter the modeling signal to generate a first output signal, the feedback path modeling adaptive filter operable to calculate feedback neutralization filter taps;
a second summing junction operable to subtract the first output signal from the modified modeling feedback signal to generate the feedback path modeling error signal which is provided to a first adaptive algorithm used by the feedback path modeling adaptive filter;
a secondary path signal discrimination circuitry operable to receive an error signal and to generate a modified modeling secondary path signal;
a secondary path modeling adaptive filter operable to receive the modeling signal and a secondary path modeling error signal and to filter the modeling signal to generate a second output signal, the secondary path modeling adaptive filter operable to calculate secondary path compensation filter taps;
and
a third summing junction operable to subtract the second output signal from the modified modeling secondary path signal to generate the secondary path modeling error signal which is provided to a second adaptive algorithm used by the secondary path modeling adaptive filter.

8 more elements

An off-line modeling system for modeling a feedback path and a secondary path, the off-line modeling system comprising:

a reference sensor operable to receive a noise signal and a feedback signal and to generate a primary signal in response;
a secondary source operable to receive a modeling signal and to provide the modeling signal through the feedback path and the secondary path;
an error sensor operable to receive a residual signal and to generate an error signal in response;
and
an off-line modeling circuitry for modeling the feedback path and the secondary path including:
a modeling signal generator operable to generate the modeling signal,
a feedback path signal discrimination circuitry operable to receive the primary signal and to generate a modified modeling feedback signal;
a feedback path modeling adaptive filter operable to receive the modeling signal and a feedback path modeling error signal and to filter the modeling signal to generate a first output signal, the feedback path modeling adaptive filter operable to calculate feedback neutralization filter taps,
a first summing junction operable to subtract the first output signal from the modified modeling feedback signal to generate the feedback path modeling error signal which is provided to a first adaptive algorithm used by the feedback path modeling adaptive filter,
a secondary path signal discrimination circuitry operable to receive the error signal and to generate a modified modeling secondary path signal, the secondary path signal discrimination circuitry including:
a decorrelation delay unit operable to delay the error signal and to generate a delayed output signal that corresponds to a delayed error signal,
an adaptive discrimination filter operable to receive the delayed output signal and the modified modeling secondary path signal and to filter the delayed output signal to generate a predicted noise signal, and
a second summing junction operable to subtract the predicted noise signal from the error signal to generate the modified modeling secondary path signal,
a secondary path modeling adaptive filter operable to receive the modeling signal and a secondary path modeling error signal and to filter the modeling signal to generate a second output signal, the secondary path modeling adaptive filter operable to calculate secondary path compensation filter taps, and
a third summing junction operable to subtract the second output signal from the modified modeling secondary path signal to generate the secondary path modeling error signal which is provided to a second adaptive algorithm used by the secondary path modeling adaptive filter.

12 more elements

An off-line modeling circuitry for modeling the feedback path and the secondary path of an active noise control system, the off-line modeling circuitry comprising:

a modeling signal generator operable to generate the modeling signal;
a feedback path signal discrimination circuitry operable to receive a primary signal and to generate a modified modeling feedback signal;
a feedback path modeling adaptive filter operable to receive the modeling signal and a feedback path modeling error signal and to filter the modeling signal to generate a first output signal, the feedback path modeling adaptive filter operable to calculate feedback neutralization filter taps;
a first summing junction operable to subtract the first output signal from the modified modeling feedback signal to generate the feedback path modeling error signal which is provided to a first adaptive algorithm used by the feedback path modeling adaptive filter;
a secondary path signal discrimination circuitry operable to receive an error signal and to generate a modified modeling secondary path signal, the secondary path signal discrimination circuitry including:
a decorrelation delay unit operable to delay the error signal and to generate a delayed output signal that corresponds to a delayed error signal,
an adaptive discrimination filter operable to receive the delayed output signal and the modified modeling secondary path signal and to filter the delayed output signal to generate a predicted noise signal, and
a second summing junction operable to subtract the predicted noise signal from the error signal to generate the modified modeling secondary path signal;
a secondary path modeling adaptive filter operable to receive the modeling signal and a secondary path modeling error signal and to filter the modeling signal to generate a second output signal, the secondary path modeling adaptive filter operable to calculate secondary path compensation filter taps;
and
a third summing junction operable to subtract the second output signal from the modified modeling secondary path signal to generate the secondary path modeling error signal which is provided to filter the modeling signal to generate a first output signal, the feedback path modeling adaptive filter operable to calculate feedback neutralization filter taps;
a first summing junction operable to subtract the first output signal from the modified modeling feedback signal to generate the feedback path modeling error signal which is provided to a first adaptive algorithm used by the feedback path modeling adaptive filter;
a secondary path signal discrimination circuitry operable to receive an error signal and to generate a modified modeling secondary path signal, the secondary path signal discrimination circuitry including:
a decorrelation delay unit operable to delay the error signal and to generate a delayed output signal that corresponds to a delayed error signal,
an adaptive discrimination filter operable to receive the delayed output signal and the modified modeling secondary path signal and to filter the delayed output signal to generate a predicted noise signal, and
a second summing junction operable to subtract the predicted noise signal from the error signal to generate the modified modeling secondary path signal;
a secondary path modeling adaptive filter operable to receive the modeling signal and a secondary path modeling error signal and to filter the modeling signal to generate a second output signal, the secondary path modeling adaptive filter operable to calculate secondary path compensation filter taps;
and
a third summing junction operable to subtract the second output signal from the modified modeling secondary path signal to generate the secondary path modeling error signal which is provided to a second adaptive algorithm used by the secondary path modeling adaptive filter.

16 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/992,933Filed 17 Dec 1997
Granted: 23 Nov 1999
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G10K 11/17817
Characterised by the analysis of the acoustic paths, e.g. estimating, calibrating or testing of transfer functions or cross-terms: between the…
G10K 11/17819
Characterised by the analysis of the acoustic paths, e.g. estimating, calibrating or testing of transfer functions or cross-terms: between the…
G10K 11/17854
Of the filter: the filter being an adaptive filter
G10K 11/17881
Using both a reference signal and an error signal: the reference signal being an acoustic signal, e.g. recorded with a microphone