A radio frequency (RF) generator includes a RF power source configured to generate an output signal at an output frequency. The RF generator includes a frequency tuning module. The frequency tuning module generates a frequency control signal that controls the output frequency of the RF power source. The frequency control signal includes a frequency tuning signal component and a perturbation signal component. The perturbation signal varies an electrical parameter of the output signal. The frequency tuning signal is adjusted in accordance with a change in output signal in response to the perturbation signal.