Patent attributes
A radio frequency receiver is provided that comprises an antenna, an RF amplifier, at least one down conversion mixer stage and a variable notch filter. The at least one down-conversion mixer stage is arranged to act on signals provided by the RF amplifier and is tuned to a tuned frequency ft which is selected from a plurality of possible tuned frequencies corresponding to a frequency of the RF signal to be received at the antenna. The variable notch filter is arranged to act on signals passing from the antenna to the RF amplifier and has a resonance frequency fr which is selected from a plurality of possible resonance frequencies such that fr=ft in where n is a whole number between 2 and 10. The variable notch filter thereby acts to attenuate signals from the antenna at said resonance frequency.
