Improvement of the narrowband linear predictive coder. Part 2: Synthesis improvements

The narrowband linear predictive coder (LPC) is widely used in both civilian and military applications. Yet in spite of improvements over the years, it is still not universally accepted by general users. This report examines the weakness of the LPC synthesizer, particularly the excitation signal. Diagnostic Acceptability Measure tests show an increase up to five points. This can be achieved without altering the speech sampling rate, the frame rate, or the parameter coding.