We propose a new intra-frame differential coding algorithm for speech waveform intime domain

This coding algorithm treats the waveforms in pre-proceeding as two-dimensionsignals.X-axis signal is the sequence number of samples in the same frame and Y-axis is thesequence number of frames

which performs the matching differential coding for the two sequentframes.Problems caused by intra-frame differential coding

such as frame matching

transitionframe proceeding and quantizer design

are discussed in detail.SNR test results for the somevowels of Mandarin Chinese is presented.The experiment shows that the short-time quantizationSNR of 4-bits intra-frame differentizal coding surpases 2 9 dB at 8kHz sampling rate. It isshown that there is a possibiliry to systhesis excellent speech with bit rate of 2 ～ 4kbps.