Datasets of multiharmonic feedback control system tests.

A multiharmonic I/Q feedback control system is designed to suppress the undesired multiple harmonics in a wideband RF cavity. In the context of I/Q control, loop-phase calibration is required because a substantial loop phase can introduce significant crosstalk between the I/Q channels, potentially leading to instability in I/Q control. The primary contributors to the loop phase are the loop delay and frequency response of the cavity and analog devices. Therefore, it is crucial to calibrate the loop phase to a minimum value to keep the condition for closing the feedback. With successful calibration for all harmonics, the multiharmonic feedback control loops can be effectively closed, significantly suppressing the undesired harmonics. This dataset includes the measured loop phases, the loop phases after calibration, as well as the harmonic components before and after the feedback loops are closed.