HOWLING SUPPRESSION DEVICE

摘要

PURPOSE:To allow the device to cope with even a sudden voice change by estimating a loop gain of a howling based on the frequency and the power level where howling takes place and subtracting a signal multiplied with a gain from an original signal. CONSTITUTION:A howling frequency and level detection section 3 detects the howling frequency, a frequency delay calculation section 4 calculates a delay equivalent to rotate the frequency component by 180 deg. and a delay section 5 retards the signal by a delay corresponding to the rotation of the frequency component by 180 deg. for the transmission signal from the microphone 1. The howling frequency and level detection section 3 obtains a reciprocal of the estimated howling loop gain and a multiplier 6 multiplied the obtained reciprocal with the transmission signal retarded by the delay section 6. An adder section 7 subtracts the multiplied signal from the transmission signal from the microphone 1 to cancel the howling frequency component.