| 摘要 |
A network simulating an ungrounded inductor includes an active gyrator circuit which employs an operational amplifier, said gyrator being a two port device having an ungrounded port, and a grounded port. The ungrounded port is terminated in a capacitor C so as to provide an input impedance, Zin, looking into the grounded port, which simulates an inductor: Zin=e1/i1=j omega R2C, where omega =2 pi f, e1 the voltage across the port and i1 is the current into the port. A current i2 is developed in the gyrator circuit, from the operational amplifier output, and appears as an extraneous current at the grounded terminal of the grounded port. An active network including a second operational amplifier is connected to the active gyrator circuit and is arranged to provide a current i3 which is equal in value to but opposite in sign from said i2 current. The current i3 is combined with the i1 and i2 currents at the grounded terminal. Because of its amplitude and sign the current i3 effectively cancels the i2 current. Thus, only the current i1 appears to pass into and out from the terminals of the grounded port and a simulated ungrounded inductor is obtained.
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