A method and system are provided for canceling interference signals from a received signal. A ratio module receives as input a ratio of a filtered receiver output signal level and a filtered transmitter output signal level. A product module receives as inputs an output of the ratio module and a transmitter output. The product module calculates a product of the output of the ratio module and the transmitter output. An adjusted receiver signal module receives a difference calculated from the received signal level and the output of the product module. The method and system are suitable for use in a metal detection subsystem with a larger security system.