an enhanced nonlinear processor for rfi suppression uses a biased inverting limiter circuit . there are two parallel paths in the device ; the first one is used to estimate the intensity of the rfi signal , the second one is used to process the signal . the first signal path employs an envelope detector and filter followed by a comparator circuit to avoid use of the processing if the rfi is too small ; the second path has a biased inverting limiter whose characteristic is controlled by the output of the first path . when the estimate of the rfi intensity is close to being correct , the biased inverting limiter traps the large rfi signal , converting it into a higher order harmonic which is filtered out . the wanted signal is not trapped , but instead sees an &# 34 ; effective &# 34 ; positive gain which allows it to pass through unaffected except for a gain factor . the net result is a reduction in the ratio of unwanted signal to wanted signal .