In theory, engineered anomalous transmission in passive materials and waveguide devices can be used to compensatefor waveform distortions. However, they suffer from inherent dissipation. Recently, active non-Fosterelements with imaginary immittance monotonically decreasing with frequency have shown important potentialsin broadening bandwidths of electromagnetic devices. So far, they are implemented based on negative impedanceconvertors (NICs) loaded with Foster devices. This makes them intrinsically one-port elements and thus cannotbe used to compensate for distortions of signals. We construct a two-port network with a non-Foster transmissioncoefficient based on an unconventional use of NICs. Simulation and experiments show that it can compensatefor extremely distorted signals. The proposed method can be used to broaden existing applications in differentareas such as antennas, circuits and systems, and physical-layer signal processing.