Digital speech coder with different excitation types

Abstract From the Canadian patent

Abstract, An improved speech analysis and synthesis system where pitch information for excitation is transmitted during voiced segments of speech and modified residual information for excitation is transmitted during unvoiced speech segments along with linear predictive coded (LPC) parameters. The speech analysis portion of the system uses a pitch detection circuit to determine when the speech is voiced or unvoiced and to calculate the pitch information during voiced segments. A multi-pulse excitation forming circuit generates the modified residual signal which is obtained from the cross correlation of the residual signal and the LPC-recreated original signal. The pitch detection circuit …