Abstract: A coupling circuit composed of an input terminal for receiving an input signal from a source and first and second output terminals for supplying an output signal to a load; a signal processing device connected between the input terminal and the first output terminal for deriving an output signal from the input signal and for supplying the output signal to a load connected between the output terminals; a power supply; connecting lines each having a finite impedance and connected for supplying operating power from the power supply to the signal processing device, a distortion eliminating circuit connected between the power supply and the second output terminal for directing load current to the signal processing device so as to bypass the load current from the line impedances, the distortion eliminating device including at least one active circuit element and having an electric characteristic corresponding substantially to a capacitor with infinite capacitance.

Abstract: A circuit for coupling a signal source producing a signal having a given voltage waveform to a load having two ends, the circuit being composed of: a load voltage control unit connectable between the signal source and one end of the load for producing across the load a voltage corresponding to the signal voltage; and a load current control unit connectable to the load and operable independently of the signal source for producing a current flow through the load sufficient to cause the voltage across the load or the current through the load to have the given waveform.