Time varying notch filter

A method comprising:

• receiving, at a filtering device, a communications signal;
• determining, by the filtering device, one or more parameters of the communications signal;
• selecting, by the filtering device, a set of filter coefficient values based on the determined one or more parameters of the communications signal;
• adjusting one or more characteristics of the filtering device using the selected set of filter coefficient values to set a frequency response of the filtering device to a first frequency response, wherein the filtering device includes a feedback section and a feedforward section, which are configured to have a delay associated with the feedback section that is different from a delay associated with the feedforward section;
• filtering, by the filtering device, the communications signal using the first frequency response of the filtering device, wherein the filtering is performed at a first time before packet data included in the communications signal is received;
• updating the set of filter coefficient values at a second time based on determining that the packet data included in the communications signal is received;
• and
• adjusting one or more characteristics of the filtering device using the updated set of filter coefficient values to set the frequency response of the filtering device to a second frequency response.