On estimation of noise variance in the presence of a narrow-band signal

The procedure for noise variance estimation in the presence of a narrow-band signal with a priori unknown parameters is discussed. The fast suppression of a narrow-band signal prior to measurement of a noise variance is accomplished with a low-order adaptive notch filter (ANF) based on a linear prediction. It is shown that a good estimation of noise variance can be obtained over the time-limited interval in spite of the presence of a strong narrow-band signal. Computer simulation results which demonstrate the proposed algorithm performance are included.