| 摘要 |
<p>In a speech detector responsive to an input signal including a speech signal, first and second circuits detect electric power of the input signal and a variation of a spectrum of the input signal to produce first and second signals representative of results of detection, respectively. The second circuit comprises an autocorrelator for calculating partial autocorrelation coefficients at a sequence of time instants and a calculation circuit for calculating a difference between the coefficients at two adjacent ones of the time instants to specify the variation of the spectrum and to produce the second signal. The first and the second signals are sent through an OR gate and a hangover circuit as an output signal representative of presence of the speech signal.</p> |
