Patent ID: 8374356

Claim:
A noise canceling apparatus comprising: a microphone configured to pick up ambient sound as noise; a first signal generator configured to receive a signal from said microphone to generate a noise cancel signal that is inverted in phase to said signal received from said microphone and has an amplitude level considered with an attenuation in accordance with a distance from said microphone to an observation point separated away from said microphone; a first loudspeaker configured to be arranged in the proximity of said microphone and output said noise cancel signal; a second signal generator configured to receive said signal from said microphone to generate a positive-phase signal that has the same phase as that of said signal from said microphone; and a second loudspeaker configured to be arranged in the proximity of said microphone and output said positive-phase signal; wherein said noise cancel signal outputted from said first loudspeaker is attenuated by said positive-phase signal outputted from said second loudspeaker to let a noise cancel signal having an amplitude level substantially equal to that of a noise cancel signal observed at said observation point reach said microphone.