Abstract:
A device for filtering electrical signals has a number of inputs (2L, 2R) arranged spatially at a distance from one another and supplying respective pluralities of input signal samples. A number of signal processing channels (10L, 10R), each formed by a neuro-fuzzy filter, receive a respective plurality of input signal samples and generate a respective plurality of reconstructed samples. An adder (11) receives the pluralities of reconstructed samples and adds them up, supplying a plurality of filtered signal samples. In this way, noise components are shorted. When activated by an acoustic scenario change recognition unit (5), a training unit (4) calculates the weights of the neuro-fuzzy filters, optimizing them with respect to the existing noise.
Abstract:
The filtering device (80) comprises a neuro-fuzzy filter (1; 80) and implements a moving-average filtering technique in which the weights for final reconstruction of the signal ( oL 3 ( i )) are calculated in a neuro-fuzzy network (3) according to specific fuzzy rules. The fuzzy rules operate on three signal features ( X 1( i ), X 2( i ), X 3( i )) for each input sample ( e ( i )). The signal features are correlated to the position of the sample in the considered sample window, to the difference between a sample and the sample at the center of the window, and to the difference between a sample and the average of the samples in the window. The filter device for the analysis of a voice signal comprises a bank of neuro-fuzzy filters (86, 87). The signal is split into a number of sub-bands, according to wavelet theory, using a bank of analysis filters including a pair of FIR QMFs ( H 0 , H 1 ) and a pair of downsamplers (85, 86); each sub-band signal is filtered by a neuro-fuzzy filter (86, 87), and then the various sub-bands are reconstructed by a bank of synthesis filters including a pair of upsamplers (88, 89), a pair of FIR QMFs ( G 0 , G 1 ), and an adder node (92).