| 摘要 |
<p>Provided is a howling canceller which outputs voice while changing the phase such that no howling occurs without relatively complicated processing. A phase control unit (2) generates a phase adjustment value ? that gradually changes with time and gives the phase adjustment value to an adjustment signal generation section (121) of a phase shifter (1). Phase adjusters (111, 112) of the phase shifter (1) output two first-stage phase adjusted signals with phases different from each other by p/2 on the basis of a shifter input signal. The adjustment signal generation section (121) generates a cosine value cos(?) and a sine value sin(?) of the phase adjustment value ? and gives the cosine value and the sine value to multipliers (123A, 123B), respectively. The multiplier (123A) multiplies one of the first-stage phase adjusted signals by the cosine value cos(?), and the multiplier (123B) multiplies the other of the first-stage phase adjusted signals by the sine value sin(?). An adder (13) adds the multiplied signals, and outputs a shifter output signal obtained by the addition and having a phase that gradually changes with respect to the shifter input signal.</p> |
