Patent ID: 6131084
Filing Date: 2000-10-10
Classification: G10L

Abstract:
A method of encoding speech into a 90 millisecond frame of bits for transmission across a satellite communication channel, the method comprising the steps of:digitizing a speech signal into a sequence of digital speech samples;dividing the digital speech samples into a sequence of subframes, each of the subframes comprising a plurality of the digital speech samples;estimating a set of model parameters for each of the subframes; wherein the model parameters comprise a set of spectral magnitude parameters that represent spectral information for the subframe;combining two consecutive subframes from the sequence of subframes into a block;jointly quantizing the spectral magnitude parameters from both of the subframes within the block, wherein the joint quantization includes forming predicted spectral magnitude parameters from the quantized spectral magnitude parameters from a previous block, computing residual parameters as the difference between the spectral magnitude parameters and the predicted spectral magnitude parameters, combining the residual parameters from both of the subframes within the block, and using a plurality of vector quantizers to quantize the combined residual parameters into a set of encoded spectral bits;adding redundant error control bits to the encoded spectral bits from each block to protect at least some of the encoded spectral bits within the block from bit errors; andcombining the added redundant error control bits and encoded spectral bits from two consecutive blocks into a 90 millisecond frame of bits for transmission across a satellite communication channel.