| 摘要 |
PURPOSE:To eliminate the need for complicated control by using a code word length as an integer multiple of 2, using the same number of symbols at a code word where the probability of generation is high, making the number of symbols different only for a code word having a low probability and making the appearance probability of the symbol for pulse coding to 1/2. CONSTITUTION:In case of the fixed code word where the code length is 2, when the probability of generation of codes S0, S1, S2 and S3 is taken respectively as 0.4, 0.3, 0.2 and 0.1, the code word symbol is formed as 01, 10, 00 and 11. The probability of generation of symbols 0, 1 is respectively 0.55 and 0.45 under the probability of generation of the code S1, and the probability is a value sufficiently close to 1/2. In case of 2 or 4-bit variable length code word, the code word is assigned to the probability of generation of the code S1 to bring the probability of generation of the transmitted symbol close to 1/2. The addition of a pseudo random signal and the switching control of the code word in response to the frequency of appearance of 0, 1 beforehand are not required by bringing the probability to 1/2 in such a way. |
