US Patent 11955942 Active multi-pole filter

An RF signal is processed by coupling an input signal into a signal loop, the signal loop comprising a resonator and a processing block, and filtering the input signal in the signal loop to produce an output signal by obtaining a plurality of resonator outputs from the resonator and processing the plurality of resonator outputs to generate feedback signals. The feedback signals are connected to a point upstream of the resonator. At least one of the plurality of resonator outputs is processed in the processing block. The signal loop is definable by a transfer function having poles, and the plurality of resonator outputs are processed such that the poles of the transfer function are independently controllable.