HOWLING CANCELLER AND HOWLING CANCELLATION METHOD

摘要

An audio feedback suppression device is provided that outputs a sound while changing a phase so as not to generate audio feedback without performing a relatively complicated process. A phase control section 2 generates a phase adjustment value ¸ gradually varying with the lapse of time and gives the value ¸ to an adjustment signal generation section 121 of a phase shifter 1. Phase adjustors 111 and 112 of the phase shifter 1 output two first stage adjusted signals having phases which are shifted from each other by À/2 in accordance with a shifter input signal. An adjusting signal generation section 121 generates a cosine value cos(¸) and a sine value sin(¸) of a phase adjustment value 0 and gives the values to respective multipliers 123A and 123B. The multiplier 123A multiplies one of the first stage phase adjusted signals to the cosine value cos(¸) and the multiplier 123B multiplies the other first stage phase adjusted signal to the sine value sin(¸). An adder 13 adds the multiplied signals together so as to output a shifter output signal having a phase gradually varying with respect to a shifter input signal.