SYSTEM IDENTIFYING DEVICE AND SYSTEM IDENTIFYING METHOD

摘要

A system identifying device for identifying an unknown system interposed between first and second input terminals. The system identifying device preferably comprises adaptive and dependent filters which receive a signal supplied through a first input terminal, a dependent filter factor updating unit for updating the filter factor of the dependent filter according to the filter factor of the adaptive filter, a first subtracter for subtracting the output signal outputted from the adaptive filter from the signal supplied through a second input terminal, a first output error mean computing section for computing a first output error mean from the output signal outputted from the first subracter, a second subracter for subtracting the output signal outputted from the dependent filter from the signal supplied through the second input terminal, a second output error mean computing section for computing a second output error mean from the output signal outputted from the second subtracter, and a comparator for comparing the first and second output error means. The first output error mean computing section computes the first output error mean from the components which are the remainder of reduction of the components of at least part of the frequency band superposed on the frequency band of the observed noise applied to the second input terminal out of the frequence band of the output signal outputted from the first subtracter. The second output error mean computing section computes the second output error mean from the components which are the remainder of reduction of the components of at least part of the frequency band superposed on the frequency band of the observed noise applied to the second input terminal out of the frequency band of the output signal outputted from the second subtracter. At least either update of the filter factor of the adaptive filter by the output signal outputted from the first subtracter or of the filter factor of the dependent filter by the dependent filter factor updating unit is controlled depending on the result of the comparison by the comparator.