| 摘要 |
PURPOSE:To adjust a sound recording level automatically, by detecting a period in which a sound recording signal level exceeds the reference level, and controlling the degree of amplification by this detecting signal. CONSTITUTION:The input terminal 31 is connected to te input of the voltage control amplifier circuit 33 through the manual level adjusting circuit 32. The amplifier circuit 33 is connected to not only the recording head 13 but also the comparator 36, through the recording amplifier 34. The reference level and the recording level are compared by the comparator 36, and according to a signal of the period in which the recording level exceeds the reference level, the voltage is swept and held by the sweep voltage generating circuit 38 during said period. The recording level is adjusted by controlling the degree of amplification of the amplifier circuit 33 by an output of the generating circuit 38. In this regard, the holding voltage is reset by the switch 39. |
