Patent ID: 8385539
Filing Date: 2013-02-26
Classification: H04B,H04M

Abstract:
1. A method for controlling adaptive filters, comprising: a first filter adapting a first signal to a first frequency range; the first filter transmitting the adapted first signal to a power determination unit and to a subtractor; transmitting the first signal to the power determination unit; the power determination unit determining a first power level for the first signal; the power determination unit determining a second power level for the adapted first signal; the power determination unit transmitting the first power level to a first comparator device; the power determination unit transmitting the second power level to a multiplier; the multiplier multiplying the second power level by a first parameter to obtain a first product; the multiplier transmitting the first product to the first comparator device; the first comparator device comparing the first product to the first power level to detect whether the first signal is a narrowband signal or a broadband signal, the first signal being determined to be a narrowband signal if the product is greater than the first power level and the first signal being determined to be a broadband signal if the product is less than the first power level; upon a determination that the first signal is a broadband signal, an adaptation unit performing an adaptation having a first step width; upon a determination that the first signal is a narrowband signal, the adaptation unit adapting the first signal to selectively eliminate narrowband echo of the first signal via adapting the first signal via a second step width that is smaller than the first step width, the adaptation unit comprising an adaptation control and a coefficient update device, the selective elimination of the narrowband echo comprising: a second filter adapting an echo signal to a second frequency range; the second filter transmitting the adapted echo signal to the subtractor; the subtractor subtracting the adapted echo signal from the adapted first signal to obtain a difference; the subtractor transmitting the difference such that an amplitude of the difference is transmitted to a second comparator device; the second comparator device comparing an amplitude of the difference with a second parameter, upon a determination by the second comparator device that the amplitude of the difference is greater than the second parameter, adaptation or further adaptation of the first signal is blocked; and upon a determination by the second comparator device that the difference is less than the second parameter, continuing adaptation of the first signal by the adaptation unit to selectively eliminate the narrowband echo.