Sub-band adaptive IIR noise cancellation

A subband adaptive infinite impulse response (IIR) noise cancellation scheme whose structure enables the cancellation of multiple sinusoidal interferences in a received speech signal is presented. Compared with the classical least mean square adaptive noise cancellation method, this new structure has two major differences. First, the quadrature mirror filter technique is used to decompose signals into subbands. Second, a new constrained adaptive IIR notch filter and adaptive IIR bandpass filter are developed to form an adaptive IIR noise canceller and used to remove the multiple-frequency, or harmonic, noise from a received speech signal. Computer simulations were done using a set of actual speech signals corrupted by car engine noise. Experiments demonstrate that more than 20-dB signal-to-noise ratio improvements can be achieved