| 摘要 |
<p>To enhance the intelligibility of speech, the consonant sounds are intensified and, in effect, their intensity equalised to that of the vowel sounds in a speech waveform. A short-time estimate of the relative spectral shape of an input speech signal is determined by envelope detectors (24) operating on the outputs of band pass filters (20). Control means are provided to respond to such relative spectral shape estimate by dynamically controlling a modification of the spectral shape of the actual speech signal so as to produce a modified output speech signal, the control means comprising a combination matrix (28) operating on the outputs of the envelope detectors (24) with a matrix of coefficients and producing weighted signals (29) as control signals. The control signals (29) act on gain selecting logic (30) to determine the gains of multipliers (31) through which respective different portions of the frequency spectrum of the input speech are coupled to a summation circuit (32) producing the consonant - enhanced output speech signal, the respective different portions of the frequency spectrum of the input speech being produced by a bank of filters (20) supplying the envelope detectors (24) or by a set of different filters (26).</p> |
