| 摘要 |
In a speech signal encoding system comprising an analyzer and a synthesizer, the analyzer is supplied with an input analog signal and selects an initial sequence of digital signals within an analysis frame. The analyzer extracts correlations from the analysis frame, which is divided into a plurality of time intervals each of which is subdivided into a plurality of phases. The correlations are calculated between autocorrelations of impulse responses within the analysis frame and cross-correlations between the digital signals and the impulse responses, for detecting by a maximum similarity series searching circuit a sequence of excitation pulses which has a maximum similarity between the autocorrelation coefficients and the cross-correlations. The excitation pulses appear at an equidistant time interval and an identical amplitude, and have a selected one of the phases and variable polarities. The excitation pulses are sent to the synthesizer together with a phase signal representative of the selected phase, an amplitude signal determined by the analyzer, and a sequence of LPC parameters calculated in relation to the analysis frame.
|
