| 摘要 |
PURPOSE:To attain efficient transmission by dividing a dynamic range into N groups and expressing the data with a fixed word length part representing a group and a variable word length word representing up to an unit quantization level in the group. CONSTITUTION:All the dynamic range is divided into N (n0-n1, n1-n2,..., nN-1-nN) level regions by M quantization levels so as to make the appearence probability of a signal corresponding to each level region equal. Then each level region is divided into a unit quantization level and when N is, e.g., 8, the fixed word length representing the group is takes as 3 bits. In order to express a detailed level in the group, the variable word length is used. In taking a dynamic range as 0-254, the variable word length part has 0-7 bits. When the appearence probability at each range region is equal, the 1-word mean bit length is nearly 6.5-bit.
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