| 摘要 |
A microphone comprising a double membrane condenser unit and an amplifier circuit is connected to a power supply. Signals from the two membranes of the unit are fed to each one amplifier and to each one impedance transformer and are delivered through a signal wire to a power supply unit having phantom power supply. In the power supply unit, the signals are added or subtracted in order to give a continuously variable directional characteristic of a round or eight characteristic and are added or subtracted in different proportions by means of a potentiometer in order to give different degrees of a cardioid characteristic. The microphone can also be used as a stereo microphone by assigning the two signals to the right and the left channel, respectively. For balanced signals an inverting buffer is used and a second impedance transformer. |
