Patent ID: 9154874
Filing Date: 2015-10-06
Classification: H04R

Abstract:
1. A howling detection apparatus comprising: a signal level calculation section that calculates, from an input signal, an input signal level that is a signal level of said input signal at a predetermined time; a level fluctuation estimated value calculation section that calculates a level fluctuation estimated value by multiplying a previous level fluctuation estimated value by a predetermined coefficient such that the level fluctuation estimated value gradually increases or gradually decreases by a predetermined amount from said input signal level over time, the predetermined coefficient being determined in accordance with the input signal level; a threshold value calculation section that calculates, from said level fluctuation estimated value, a level threshold value by changing the level threshold value according to said level fluctuation estimated value; and a howling determination section that determines that howling has occurred in the input signal on a condition that a state in which said input signal level exceeds said level threshold value continues in excess of a predetermined time threshold value.