NOISE REDUCTION WITH INTEGRATED TONAL NOISE REDUCTION

摘要

The system provides a technique for suppressing or eliminating tonal noise i n an input signal. The system operates on the input signal at a plurality of frequency bins and uses information generated at a prior bin to assist in calculating value s at subsequent bins. The system first identifies peaks in a signal and then determines if t he peaks are from tonal effects. This can be done by comparing the estimated background noise of a current bin to the smoothed background noise of the same bin. The smoothed background noise can be calculated using an asymmetric IIR filter. When the ratio of th e current background noise estimate to the currently calculated smoothed background noise is far greater than 1, tonal noise is assumed. When tonal noise is found, a number of suppression techniques can be applied to reduce the tonal noise, including gain suppression with fixed floor factor, an adaptive floor factor gain suppressi on technique, and a random phase technique.