| 摘要 |
PROBLEM TO BE SOLVED: To obtain a usable channel number and to efficiently use frequencies by performing frequency hopping by using a frequency of a group whose communication quality is low in communicating data which has low significance. SOLUTION: Transmission data comprises high order classes B1 to BN and low order classes b1 to bn. A secondary encoder 22 which performs frequency hopping is provided with tables. It is provided with a conversion table 24 for the high order classes and a conversion table 26 for the low order classes as a frequency conversion table. Frequency patterns of the high order classes are converted into frequencies F1 to FN by using the table 24, while frequency patterns for low order classes are converted into frequencies f1 to fn by using the table 26. Thereby, data which has low significance is transmitted by a frequency channel whose communication quality is not high. Then, a frequency channel that has a good communication quality can be assigned to other significant data. |
