SYSTEM, METHOD AND APPARATUS FOR CANCELLING NOISE

摘要

A system for cancelling and reducing an audio signal noise arising from electrical or electromagnetic noise sources such as AC to DC power converter used by computers. The system receives a digital audio signal (102) sampled at a frequency which is at least twice the bandwidth of the audio signal. The input samples are stored in a temporary buffer of 256 points (104). when the buffer is full, the new 256 points are combined in a combiner (106) with the previous 256 points to provide 512 input points which are multiplied by multiplier (108) with a shading window with the length of 512 points. The shaded results are converted to the frequency domain through an FFT processo r (110). The FFT output is processed in a noise processor (112) which includes the noise magnitude estimation for each frequency bin, the substraction that estimates the noise free complex value for each frequency bin and the residu al noise reduction process.