Subtractive cancellation of harmonic noise

A Kalman filter, sinusoidal perturbation technology, applied in speech analysis, speech recognition, instrumentation, etc., can solve problems such as slowing down estimation, estimator unable to track changes in amplitude and phase, and not saving the content of the information-bearing spectrum

Inactive Publication Date: 2005-11-30
HONDA RES INST EUROPE
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Problems solved by technology

However, a major disadvantage of this method is that it does not preserve the information-bearing spectral content at the notch frequency
[0005] Once a good estimate has been found, the estimation process can be slowed down or stopped entirely so that the estimator cannot track changes in amplitude and phase caused by the signal of interest

Method used

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  • Subtractive cancellation of harmonic noise
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Embodiment Construction

[0031] compensation method

[0032] The overall compensation method of the present invention is described below with reference to FIG. 1 , which proposes to eliminate noise in a disturbed signal by adding reference noise.

[0033] As can be seen from Fig. 1, the method proposed by the present invention estimates (2) and tracks the following parameters for each disturbance: in-phase amplitude, quadrature amplitude and frequency. This estimation is done recursively by an extended Kalman filter. Subsequently, based on the three estimated parameters (3), a reference signal (5) is generated (4) and subtracted (6) from the perturbed signal (1) to compensate for the Sinusoidal disturbance (9).

[0034] The reference signal used is an artificial signal (5) generated from a noise model (4) This artificial signal represents an estimate of the actual disturbance noise (9) superimposed on the information-bearing signal (8) s(n). The estimation of the reference signal (2) is done indi...

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Abstract

A common problem in audio processing is that a useful signal is disturbed by one or more sinusoidal noises that should be suppressed. One embodiment of the invention provides a method of canceling a sinusoidal disturbance of unknown frequency in a disturbed useful signal. The method comprises the steps of estimating parameters of the sinusoidal disturbance including amplitude, phase and frequency; generating a reference signal on the basis of the estimated parameters; and subtracting the reference signal from the disturbed useful signal. The estimation is performed by an Extended Kalman filter.

Description

technical field [0001] The present invention relates generally to the field of noise suppression, and more particularly to a method of eliminating additive sinusoidal disturbances of unknown frequency in a signal of interest. The method focuses on improving the quality of the video signal. The invention is however not limited to the field of acoustics, ie it can be applied to signals of pressure sensors. Background technique [0002] A common problem in audio processing is the interference of an information-bearing signal by one or more sinusoidal signals. The traditional way to suppress these interfering signals is to use a fixed notch filter tuned to the sinusoidal interfering frequency, as described in "Halbleiter-Schaltungstechnik" (by Ulrich Tietze and Christoph Schenk, Springer, 12th edition, 2002). [0003] In order to only slightly degrade the quality of the signal of interest, the notch of the filter is required to be very steep, and for good rejection, the freque...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10L21/0208
Inventor 弗兰克·茹布兰马丁·黑克曼比约恩·舍夫林
Owner HONDA RES INST EUROPE
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