Coefficient updating method for an adaptive filter
AssigneeFujitsu Limited
InventorTadashi Ohashi
Life of this patent
Estimating the term…
Abstract
A coefficient updating method stops updating filter coefficients for a plurality of adaptive filters when a convergence condition is achieved. Active noise control within a system simulates an original noise signal with a simulated noise signal which is equal and opposite to the original noise signal. To detect feedback in such a system, a reference signal or "white noise" is generated by a speaker, transmitted through the system and received by a microphone. Coefficients of multiple filters such as an anti-feedback filter, a C filter, and a noise control filter are then updated to minimize adverse parameters such as original noise and feedback. Coefficient updating of the adaptive filters is stopped when a minimum average value is reached.
Claims16
A coefficient updating method comprising the steps of:
- inputting a reference signal to a signal transmission system, a first adaptive filter, and a second adaptive filter;
- receiving the transmitted reference signal from the signal transmission system;
- subtracting an output of the first adaptive filter from the transmitted reference signal to determine a first error signal;
- updating filter coefficients of said first adaptive filter to minimize the first error signal;
- subtracting an output of the second adaptive filter from the transmitted error signal to determine a second error signal;
- updating filter coefficients of said second adaptive filter to minimize the second error signal;
- determining a minimum value of said second error signal;
- and
- stopping the coefficient updating of said first and second adaptive filters when the second error signal is the minimum value.
An adaptive filter coefficient updating method comprising the steps of:
- inputting a reference signal from a reference signal generator to an acoustic feedback transmission system, an anti-feedback filter, and an auxiliary filter;
- receiving the transmitted reference signal from the signal transmission system;
- subtracting an output of the anti-feedback filter from the transmitted reference signal to determine a first error signal;
- updating coefficients of the anti-feedback filter to minimize the first error signal;
- subtracting an output of the auxiliary filter from the transmitted reference signal to determine a second error signal;
- updating coefficients of the auxiliary filter to minimize the second error signal;
- and
- stopping the coefficient updating of said anti-feedback filter and the auxiliary filter when the second error signal reaches a minimum value.
An adaptive filter coefficient updating method comprising the steps of:
- inputting a reference signal from a reference signal generator to a transmission system and a first filter;
- subtracting an output of the first filter from the transmitted reference signal to determine an error signal;
- updating coefficients of the first filter in response to the error signal;
- inputting the error signal into an estimation scattering filter;
- updating coefficients of the estimation scattering filter to simulate the transmission system;
- and
- stopping coefficient updating of said estimation scattering filter when the error signal reaches a minimum value.
Dependencies are inferred from the claim text.