Fast Excitation Coding for Speech Coders

摘要

A speech coder formed with a digital speech encoder and a digital speech decoder uses a fast excitation coding to reduce the computational power needed to compress the digital samples of the input speech signal, thereby decompressing the compressed digital speech data stream to synthesize digital output speech samples. Generates. Many fast excitation codings are provided by the excitation search device of the encoder. The search device determines excitation information that defines an aperiodic group of excitation pulses. The optimal position of each pulse of the aperiodic pulse group is selected from the corresponding set of pulse positions stored in the encoder. The search apparatus determines the optimal pulse position by maximizing the correlation between (a) the target group of the filtered version of the digital input speech sample provided to the encoder for compression and (b) the corresponding group of synthesized digital speech samples. . The synthesized group of samples depends on the pulse position used in the corresponding set of stored pulse positions and the sign of the pulse at that pulse position.