Abstract: A strong electrical signal, occurring at the same time as a relatively wer electrical signal of substantially the same frequency, is suppressed by a method utilizing apparatus wherein (a) the signals are amplified both linearly and non-linearly simultaneously in separate amplifiers, and (b) the outputs of the amplifiers are subtracted from each other while the gain is adjusted in at least one of the amplifiers until the stronger signal is amplified to the same amplitude in each amplifier, leaving the weaker signal isolated as the resultant difference.