| 摘要 |
PURPOSE:To withstand noise and to perform improved transmission by detecting the transmission conditions of a transmission line on a reception side and changing the respective spreading ratios of a transmission side and the reception side to be larger as the detected transmission conditions get worse. CONSTITUTION:Error detection signals are counted at a transmission line condition detection part 32, the counted value is taken out by each fixed cycle, counting is reset and the conditions of the transmission is judged based on the taken out counted value. A spreading code and an information speed are selected corresponding to the judged conditions of the transmission line 17 and set at a spreading code generator 21. At the same time, selection information for indicating the selected spreading code and information speed is transmitted through a feedback transmission line 34 to the transmission side 11. A transmission control part 35 sets the spreading code and the information speed of the spreading code generator 15 based on the selection information. Thus, when the environment of the transmission line 17 gets worse, the spreading code with a long code length and the corresponding slow information speed are set, the spreading ratio becomes large and the transmission is performed so as to hardly generate errors even against the noise. |
