Patent ID: 8103504

Claim:
An electronic appliance comprising: a speaker which subjects a first voice signal generated from the electronic appliance to electricity-sound conversion to output a converted first sound wave; a sound detector which detects a second sound wave where a specific sound wave generated for control of the electronic appliance is superimposed on a third sound wave based on the first sound wave emitted from the speaker and which subjects the second sound wave to sound-electricity conversion to output a second voice signal, wherein the third sound wave is originally the same signal as the first sound wave but having different component and amplitude owing to a transmission characteristic along a path from the speaker to the sound detector; a first waveform generator which subjects the first voice signal to predetermined signal processing to generate a first waveform signal; a second waveform generator which subjects the second voice signal output from the sound detector to predetermined signal processing to generate a second waveform signal; a waveform shaping unit which enlarges the first waveform signal in a time axis direction to output a third waveform signal; a subtracter which subtracts the third waveform from the second waveform signal to output a fourth waveform signal of the specific sound wave; wherein the first waveform generator includes a first offset component removal section to generate a voice signal, and a first absolute value forming circuit which forms an absolute value of the voice signal output from the first offset component removal section to output the first waveform signal, and the second waveform generator includes a second offset component removal section to generate a voice signal in which an offset component is removed from the second voice signal, and a second absolute value forming circuit which forms an absolute value of the voice signal output from the second offset component removal section to output the second waveform signal.