| 摘要 |
PURPOSE:To hear only a generated sound by inverting an acquired external sound signal by an external sound control means and outputting the signal to an earphone after superposing processing with the sound signal. CONSTITUTION:The signal of external sound acquired by a microphone is inverted by the external sound control means 4, its output value is adjusted, and the signal is mixed by a mixer 5 with the sound signal from a sound signal generating means 1. The mixed sound signal is converted by the earphone 2a into a sound, which reaches the eardrum, but an external sound acquired by a microphone 2b also reaches the eardrum, so that the actual external sound and a reflected external sound cancel each other. Consequently, only the original sound from a sound signal generating means 1 can be heard. |
