Ääniaktiviteetin tunnistaminen

The detector calculates autocorrelation coefficients, R(k) for a signal. A first vector (RO) is composed from a first series, K = 0 ... (N-q), and a second vector (Rq) is formed from the components, k = q ...N. which are shifted by q relative to the first. The first vector is subtracted from the second to yield a difference vector, delta, R, from which a first standard vector is obtained. A reduced standard is obtained by dividing the first standard vector by a reduction value to give a second indicator. The reduction value is calculated from the energy of the audio signal or the sum of the audio energy and a bottom value, C. The linear combination of the present and previous value give a third indicator and these are measured against a threshold.