PURPOSE: To achieve effective noise canceling at the position where noise canceling is be truly needed.
CONSTITUTION: A reference signal generating part 22 outputs a signal corresponding to the noises generated by a noise source 21 as a reference signal d (n), and the respective error detecting means 23, 24 detect the synthesized sound of the noises at the respective noise canceling points and the canceling sound, and outputs the synthesized sound signal as error signals e1 (n), e2 (n). A canceling unrequired points indicating part 26 identifies noise canceling points where no noise canceling is required, and an evaluation signal generating part 27 generates an evaluation signal 3 (n) by adding the square of the error signals only at the noise canceling points where noise canceling is required. The reference signal d (n) and the evaluation signal e (n) are received by a noise canceling controller 28, and the noise canceling signal is generated by realizing digital processing to the reference signal so that the evaluation signal may be minimized, and a canceling sound is emitted from a speaker 30.
IMAI KENJI
SAITO NOZOMI
IMANISHI SHUNICHI
YOSHIDA TOSHIAKI
