| 摘要 |
PURPOSE:To allow the device to listen easily to a voice of a person in the middle when left and right audio signals are reproduced and heard by adding a signal resulting from amplifying a middle frequency component of a sum audio signal to the left and the right audio signals. CONSTITUTION:Left and right audio signals L, R from input terminals TL1, TR1 are fed to a middle frequency extract amplifier 1 and also fed respectively to left and right adders 2, 3. An output of the middle frequency extract amplifier 1, that is, the middle frequency component of L+R is added to the left and right audio signals L, R at the adders 2, 3. Then the outputs of the adders 2, 3 are fed respectively to left and right low frequency cut-off circuits 4, 5, in which the low frequency component is cut off and the result is fed to low frequency amplifiers A1, A2, from which the signal is led to left and right output terminals TLO, TRO. |
