| 摘要 |
<p>PURPOSE:To improve the use efficiency of a memory to reduce the memory capacity by sharing a table between encoding from a variable length code to a fixed length code and encoding from the fixed length code to the variable length code so as to store one code in one address of the table. CONSTITUTION:Addresses 1 to 23 of a memory 110 are used for the fixed length code, and a corresponding variable length code, the code length, a fixed length code having a high appearance probability, and a bit shift control flag are pre-liminarily stored in each of these addresses. The fixed length code is encoded to the variable lengh code by the table look up method. That is, the fixed length code is inputted from a terminal 102 and is set to a register 109 through a selector 105, and next, the input fixed length code in the register 109 is used as the address to refer to the memory 110. At the time of encoding from the variable length code to the fixed length code, the address of the table is successively changed, and the input variable length code and contents of the table are compared with each other by a comparator 107, and the address for coincidence is obtained to obtain the fixed length code.</p> |
