Spur attenuation devices, systems, and methods

A method of filtering a signal, comprising:

• transmitting an input signal comprising a desired component and at least one undesired component to a subtractor;
• transmitting at least one of the input signal and an output signal of the subtractor through a feedback loop configured to generate a feedback signal comprising at least one undesired component, wherein each undesired component of the input signal corresponds to an associated undesired component of the feedback signal;
• and
• subtracting the feedback signal from the input signal to generate an output signal.

A system, comprising:

• an antenna;
• at least one of a transmitter and a receiver coupled to the antenna;
• and
• at least one filtering device operably coupled to at least one of the transmitter and the receiver and configured to receive a signal from a local oscillator, each filtering device comprising:
• a subtractor configured to receive an input signal and convey an output signal, wherein the input signal comprises a dominant response and at least one spurious response;
• and
• a feedback loop operably coupled to the subtractor and configured to receive at least one of the input signal and the output signal, generate a feedback signal having at least one spurious response corresponding to the at least one spurious response of the input signal, and convey the feedback signal to the subtractor;
• wherein the subtractor is configured to generate an output signal by subtracting the feedback signal from the input signal.