METHOD AND DEVICE FOR THRESHOLD NOISE REDUCTION WITH AUTOMATIC THRESHOLD DETECTION Russian patent published in 2009 - IPC H04B1/64 

FIELD: physics; communications.

SUBSTANCE: proposed method and device for threshold noise reduction of audio signals relates to instrument making and is aimed at processing signals. Original signal is combined to its Hilbert conjugate, after which the square of the envelope of the original signal is selected. By determining the sum of the squares of each pair of Hilbert signal conjugates, the output signal is generated by multiplying one of the conjugates with noise reduction sub-signal, whose value is limited. From the square of the envelope of the original signal, square root is taken. By calculating the envelope of the original signal, result is integrated, scale changed, compounded with DC voltage, determining noise reduction threshold of quiet interval, forming slowly changing part of limiting threshold. From the envelope of the original signal, result obtained from integration and scaled change is subtracted, limited from below, subjected to scaled change, and limited from above, using DC voltage as the threshold, determining the noise reduction threshold of the quiet interval, forming the fast changing part of the limiting threshold, which is subtracted from the slowly changing part of the limiting threshold, forming the limiting threshold of the envelope. The fast changing part of the limiting threshold is limited from above. The result from limiting is divided by the threshold value, thereby generating the noise reduction sub-signal.

EFFECT: higher quality of audio signals and increased intelligibility of speech signals.

2 cl, 1 dwg