| 摘要 |
PURPOSE:To reject impulse noise without giving much damage to an original signal, by outputting an input signal as it is when no impulse noise is superimposed and rejecting the high-frequency band component by noise period if any impulse noise is superimposed. CONSTITUTION:An input signal is respectively applied to low- and high-pass filters 11, 12 via a buffer 20 and a delay circuit 21. On the other hand, the impulse noise component included in a music signal in the buffer 20 is detected at an impulse detecting circuit 22 and applied to a switch circuit 14 as a control signal via a driving circuit 23. The low-pass filter 11 has a transfer function F(s) as shown in (a) which rejects impulse noises. Further, since the high-pass filter 12 has a complementary transfer function 1-F(s) as shown in (b), the contact of a switch 14 is closed if no impulse noise is included in the music signal, allowing to reject impulse noises effectively without giving damage to the music signal as shown in (c). |
