Effects of UHF stimulus and negative feedback on nonlinear circuits

We investigate the combined effect of rectification and nonlinear dynamics on the behavior of several simple nonlinear circuits. We consider the classic resistor-inductor-diode (RLD) circuit driven by a low-frequency (LF) source when an operational amplifier with negative feedback is added to the circuit. Ultra-high-frequency (UHF) signals are applied to the circuit, causing significant changes in the onset of LF period doubling and chaos. Measurements indicate that this effect is associated with a dc voltage induced by rectification of the UHF signal in the circuit. The combination of rectification and nonlinear circuit dynamics produce qualitatively new behavior, which opens up a new channel of radio frequency interference in circuits.