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    SPEECH CODING METHODS AND APPARATUS FOR CARRYING OUT THE METHOD
    1.
    发明专利
    SPEECH CODING METHODS AND APPARATUS FOR CARRYING OUT THE METHOD 未知

    公开(公告)号：DE3171990D1

    公开(公告)日：1985-10-03

    申请号：DE3171990

    申请日：1981-04-30

    Applicant: IBM ,  IBM FRANCE

    Inventor： BERAUD JEAN-PAUL ,  ESTEBAN DANIEL ,  GALAND CLAUDE

    IPC: H03M3/02 ,  H03M7/30 ,  H04B1/66 ,  H04B14/04

    Abstract: This improved speech signal Block Coded PCM (BCPCM) system reduces the number of bits allocated to transmitting the scale factor, thereby releasing bits for allocation to coding samples in the associated block of samples. The scale factor (c) is calculated for every 16 millisecond block of samples. However, the scale factor will be transmitted only once per 32 millisecond block if there is no significant difference between the two sequential values. The original speech signal is split into 16 frequency subbands, each subband initials sampled and 12-bit coded, then requantized in BCPCM at dynamically variable bit rates depending on the scale factor transmission rate.

    SPEECH CODING METHOD AND DEVICE FOR IMPLEMENTING THE IMPROVED METHOD
    3.
    发明专利
    SPEECH CODING METHOD AND DEVICE FOR IMPLEMENTING THE IMPROVED METHOD 未知

    公开(公告)号：CA1188423A

    公开(公告)日：1985-06-04

    申请号：CA401879

    申请日：1982-04-28

    Applicant: IBM

    Inventor： BERAUD JEAN-PAUL ,  ESTEBAN DANIEL ,  GALAND CLAUDE

    IPC: H03M3/02 ,  H03M7/30 ,  H04B1/66 ,  H04B14/04 ,  H03M7/50

    Abstract: IMPROVED SPEECH CODING METHOD AND DEVICE FOR IMPLEMENTING THE IMPROVED METHOD Method for coding a speech-originating signal. The spectrum of the initial signal covering a frequency range of 0-4000 Hz is split into 16 subbands, each one containing 12-bit coded samples. The samples of the 16 sub-bands are requantized in BCPCM at dynamically variable bit rates. For this, the sample flow of the sub-bands is divided into blocks of a given duration, then each block is processed for deriving therefrom two scale factors, the difference of which is analyzed to define the sample block as transient or non-transient block. For each non-transient block, only one scale factor is retained, whereas for a transient block, both scale factors are retained. The signal samples of the 16 subbands are then dynamically requantized with an overall number of bits depending on whether the block considered is transient or non-transient.

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