A distributed amplifier, or if desired, an oscillator can be constructed using an active transmission line. The active transmission line, in turn, can be constructed using an auxiliary conductor inductively coupled to the primary conductor. The auxiliary conductor is driven by the primary conductor through an active shunt network distributed along the transmission line. The auxiliary conductor is placed close enough to the primary conductor so that the two conductors have a substantial amount of mutual inductance as compared to their self-inductance. In a variation of this system, the transmission line can be operated in differential mode. In one embodiment, a combination of conductance and transconductance are used to achieve gain in the transmission line for high frequency signal transmission. With absorbing terminations, the active transmission line constitutes an amplifier. With reflective terminations, the active transmission line constitutes an oscillator.