  Linear prediction (LP) technique estimates an optimum all-pole filter of a
given order for a frame of speech signal. The coefficients of the all-pole
filter, 1/A(z) are referred to as LP coefficients (LPCs). The gain of the
inverse of the all-pole filter, A(z) at z = 1, i.e, at frequency = 0, A(1)
corresponds to the sum of LPCs, which has the property of being lower (higher)
than a threshold for the sonorants (fricatives). When the inverse-tan of A(1),
denoted as T(1), is used a feature and tested on the sonorant and fricative
frames of the entire TIMIT database, an accuracy of 99.07% is obtained. Hence,
we refer to T(1) as sonorant-fricative discrimination index (SFDI). This
property has also been tested for its robustness for additive white noise and
on the telephone quality speech of the NTIMIT database. These results are
comparable to, or in some respects, better than the state-of-the-art methods
proposed for a similar task. Such a property may be used for segmenting a
speech signal or for non-uniform frame-rate analysis.
