Patent ID: 9100736
Filing Date: 2015-08-04
Classification: H04R

Abstract:
1. A method of determining a system parameter sp in a gain loop of an audio processing system, the audio processing system comprising a) a microphone system comprising a1) a number P of electric microphone paths, each microphone path MP a1.1) a microphone M a1.2) a unit SUM a1.3) a beamformer filter g wherein the microphone M a2) a summation unit SUM b) a signal processing unit for applying a, time-varying, frequency dependent gain G to said resulting input signal or a signal originating therefrom to a processed signal; c) a probe signal generator for inserting a probe signal w in the forward path, the probe signal exhibiting predefined properties and having a short-time power spectral density S d) a loudspeaker unit for converting said processed signal or a signal originating therefrom u to an output sound; said microphone system, said signal processing unit and said loudspeaker unit forming part of a forward signal path; e) an adaptive feedback estimation system comprising a number of internal feedback paths IFBP the forward signal path, together with said external and internal feedback paths defining said gain loop, the method comprising S1a) determining an expression of an approximation of the expected square of the stationary loop gain, LG wherein |A(ω)| is the magnitude response of the enhancement filter, G S1b) determining an expression of the convergence or decay rate of the expected square of the stationary loop gain, LG S2) determining a system parameter sp, from one of said expressions under the assumption that other system parameters are fixed.