Comparison of several techniques for adaptive band-stop filters

Adaptive band-stop filters used for attenuation of narrow-band interference in spread-spectrum receivers or due to resonances in control systems and instrumentation are becoming more common as we pack more signals into limited bandwidth. Two techniques for implementing these adaptive band-stop filters include adaptive heterodyne filters and adaptive filters based on pre-stored filter coefficients. Simulations show that adaptive heterodyne filters have strong advantages in the case of high-speed applications particularly when the band-stop filter requires many taps with the pre-stored coefficient technique having advantages in low-speed applications and applications that can be achieved with a small number of filter taps.