| 摘要 |
The present invention relates to a speech processing system having an encoder comprising means for receiving successive samples of PCM encoded speech signals, means for applying sequential groups of said PCM encoded speech signals as primary vector signals to an encoder code book memory for selecting code words stored in said memory most closely approximating said vector signals, means for outputting to an output line said selected code words at a first bit rate, means for converting said selected code words to converted vector signals, means for comparing the primary vector signals and converted vector signals and for providing difference signals therefrom, means for quantizing the difference signals and for providing quantized error signals, means for applying the quantized error signals to the output line at the first or at a second bit rate to enable the processing system to transmit said speech signals at an effective bit rate constituting double the first bit rate or the sum of the first and second bit rate, or for inhibiting the quantized error signals from being applied to the line whereby the processing system can transmit said speech signals at an effective rate of the first bit rate thus increasing the traffic carrying capacity of the line. |
