| 摘要 |
A switching circuit comprises an operational amplifier with two resistive negative feedback paths including respective unilaterally conducting devices (e.g. diodes) connected in opposite polarity to the output of the amplifier. A first terminal is connected to the electrode of the unilaterally conducting device in one path remote from the output of the amplifier, and a second terminal is connected to the electrode of the unilaterally conducting device in the other path remote from the output of the amplifier. Signals of one polarity only applied to the first terminal appear at the second terminal and signals of the opposite polarity only applied to the second terminal appear at the first terminal. The circuit may include three or more such feedback paths. The values of the resistors in the feedback paths may be adjusted to charge the transfer gain of the circuit. The circuit is of particular value in a telephone conference amplifier using unilateralised signals for connecting each channel to a point common to the channels. |
