| 摘要 |
PURPOSE:To eliminate the effect of pulsive noise by stopping the sampling operation of a sample holding circuit to keep the previous values, if noise is detected while sampling. CONSTITUTION:If multipath interference occurs while sample holding circuits 22 and 23 carry out sampling, a HPF26 detects a harmonic distortion component included in a composite signal. The detected signal is converted to a DC component by a wave detection circuit 28 through an amplifier 27, and, if a comparison circuit 29 interprets that the level exceeds a fixed reference level, the operation of a mono-multi 18 is forced to stop via an AND gate 31. As a result, multipath interference can be avoided. If a sampling command signal is not given to the circuit 22 from the mono-multi 18, the circuit 22 keeps the previous hold value as it is. Accordingly, a sharp and large level variation due to multipath interference can be suppressed, and thus noise, which appears on a sound output, becomes very small. |
