| 摘要 |
PURPOSE:To improve the linearity of a compressing stretching characteristic by providing a bias means to add a bias voltage, in which the detecting voltage of a detecting device comes to a zero potential, to a sound signal compressing device and a sound signal stretching device when the signal inputted to the detecting device is a noise component only. CONSTITUTION:For a voltage control amplifier 14 of a sound signal compressing device 1, an amplification factor is controlled at a detecting voltage E10 of a detecting device 13. For a voltage control amplifier 34 of a sound signal stretching device 3, the amplification factor is controlled at a detecting voltage E30 of a detecting device 33. A bias circuit 15 adds a bias voltage in which the detecting voltage E10 comes to be the zero voltage when the level of the sound input signal is zero and the signal inputted to the detecting device 13 is the noise component only. A bias circuit 35 adds the bias voltage so that the detecting voltage E30 can be the zero voltage when a sound signal component is not included in a reproducing signal and is a noise component only. Namely, at the sound signal compressing device 1 and the sound signal stretching device 3, the reduction of the linearity of the compression characteristic and the stretching characteristic due to the noise component will not occur even at the low level area of the input signal.
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