| 摘要 |
PURPOSE:To always listen to sound without any noise even when the titled equipment is used at a noisy place by subtracting a pseudo noise signal from acoustic signal inputted to a headphone by a subtractor in advance. CONSTITUTION:In a noise canceller 15, when an output signal V of an amplifier 7 is zero, an adaptive filter is operated so as to bring a residual signal E outputted from a subtractor to zero by the control of a level ditector 18. A pseudo noise Y outputted from the noise canceller 15 is subtracted from the output signal V of the amplifier 7 by the subtractor 17 to form a headphone signal W. The signal W is reproduced by the headphone 9 to form a sound signal, since the noise is listened to ears, the signal S listened to by the ears is a signal V and then only a pure sound signal from a cassette tape 3 having no noise is listened to the ears.
|
