Abstract: An impedance-generating device that provides a resistance and a reactance that are non-linear functions of a signal over a wide impedance range (VariablE Non-Linear Impedance Circuit Electronics, "VENICE"). An electronic component that has a gain characteristic with a unity gain frequency that is directly proportional to that signal can be configured to generate such an impedance. Such an electronic component configured to provide a negative effective resistance and a variable non-linear reactance can be used to implement a high frequency harmonic generator. This generator can provide high order harmonics which can be used in high frequency communications systems. The electronic component can also be configured to provide only a voltage-variable non-linear reactance which can be used to implement a reactive mixer to frequency shift a high frequency signal to an intermediate frequency signal, from mixing the high frequency signal with a local oscillator signal.