A jammer canceller to reduce a narrowband interference in an input signal received via a power line in a power line communication system, comprising: a jammer remover to remove the narrowband interference from the input signal and to generate a jammer-canceled signal using an adaptive filtering procedure, the jammer remover comprising a band-pass filter having an adaptable parameter that controls a resonant frequency to band-pass the input signal to produce a band-passed signal, an adaptation circuit coupled to the band-pass filter to vary the resonant frequency adaptively using a stochastic gradient based procedure, and a subtractor coupled to the band-pass filter to generate an error signal using the input signal and the band-passed signal, the error signal representing the jammer-canceled signal; characterized in that the jammer canceller further comprises: a jammer detector coupled to the jammer remover to detect the interference, the jammer detector comprising an energy detector to generate a signal energy in the band-passed signal, a comparator coupled to the energy detector to compare the signal energy with a pre-determined threshold, and a jammer flag generator coupled to the comparator to generate an indicator that indicates if the interference is present in the input signal; and a selector coupled to the jammer remover and the jammer flag generator to select the input signal or the jammer-canceled signal according to the indicator. a band-pass filter having an adaptable parameter that controls a resonant frequency to band-pass the input signal to produce a band-passed signal, an adaptation circuit coupled to the band-pass filter to vary the resonant frequency adaptively using a stochastic gradient based procedure, and a subtractor coupled to the band-pass filter to generate an error signal using the input signal and the band-passed signal, the error signal representing the jammer-canceled signal; characterized in that the jammer canceller further comprises: a jammer detector coupled to the jammer remover to detect the interference, the jammer detector comprising an energy detector to generate a signal energy in the band-passed signal, a comparator coupled to the energy detector to compare the signal energy with a pre-determined threshold, and a jammer flag generator coupled to the comparator to generate an indicator that indicates if the interference is present in the input signal; and a selector coupled to the jammer remover and the jammer flag generator to select the input signal or the jammer-canceled signal according to the indicator. a jammer detector coupled to the jammer remover to detect the interference, the jammer detector comprising an energy detector to generate a signal energy in the band-passed signal, a comparator coupled to the energy detector to compare the signal energy with a pre-determined threshold, and a jammer flag generator coupled to the comparator to generate an indicator that indicates if the interference is present in the input signal; and an energy detector to generate a signal energy in the band-passed signal, a comparator coupled to the energy detector to compare the signal energy with a pre-determined threshold, and a jammer flag generator coupled to the comparator to generate an indicator that indicates if the interference is present in the input signal; and a selector coupled to the jammer remover and the jammer flag generator to select the input signal or the jammer-canceled signal according to the indicator.