| 摘要 |
PURPOSE:To make it possible to use a semiconductor integrated circuit device for both monophonic and stereophonic systems by switching and connecting the 1st and 2nd input terminals to which the 1st and 2nd input signals are supplied to the non-inversional input terminal of an operational amplifier circuit in accordance with recording or reproducing time. CONSTITUTION:At the time of recording, the 2nd input signal from the input terminal 2 and an output signal from a decoder circuit 20 in a noise reduction circuit are supplied to the operational amplifier circuit 4 by switching means 3, 5, 12 to constitute an encoder circuit in the noise reduction circuit by both the circuits 4, 20 and the 1st input signal from the input terminal 1 is supplied to a voice amplifier circuit 13. In the stereophonic system using the two semiconductor integrated circuit devices, the sum or difference signal of right and left voice signal from a matrix circuit is recorded through the encoder circuit in the noise reduction circuit constituted of both the circuits 4, 20 and the right or left voice signal can be monitored at the time of recording, the device is used for both the monophonic and stereophonic systems in common. |
