An adaptive FIR filter having restricted coefficient ranges.

摘要

The adaptive FIR filter comprises a foreground non adaptive filter (11) and a background adaptive filter (12). The background filter has N tap stages, some of which have their coefficient values applied to a summator. The output of the summator is compared with a predetermined constant K and produces an update enable signal. This signal controls a switch which corrects the output of a discriminator (10). The discriminator compares the performance of the foreground and background filter, to either the foreground filter or the background filter to prevent the coefficient values of the foreground filter being updated by the background filter when the coefficient values of the background filter are unsatisfactory.