HOWLING SUPPRESSION DEVICE, HEARING AID, HOWLING SUPPRESSION METHOD, AND INTEGRATED CIRCUIT

摘要

This howling suppression device is provided with a subtractor (102) that subtracts a pseudo-feedback signal from an input signal, an adaptive filter (107) that generates a pseudo-feedback signal for the next input signal, and a coefficient-update control unit (108) that controls the update rate of filter coefficients for the adaptive filter (107). The coefficient-update control unit (108) is provided with the following: a level computation unit that computes the signal level of the input signal; a signal-rise detection unit that detects a rise position at which the increase per unit time of the signal level of the input signal exceeds a threshold; a reverberation-segment detection unit that detects a reverberation segment extending from the aforementioned rise position to the position at which the signal level of the input signal no longer falls within a prescribed range that becomes gradually narrower over time; and an update-rate control unit that sets the update rate to a first rate in the aforementioned reverberation segment and sets the update rate to a second rate in segments other than the reverberation segment, said second rate being faster than the first rate. The filter coefficients for the adaptive filter (107) are updated at the update rate set by the update-rate control unit.