| 摘要 |
PURPOSE: To improve the error at the time of detecting the validity of data by giving a difference between the transmission power level of a preamble signal for synchronism acquisition and that of a data signal. CONSTITUTION: In a demodulation part, the validity of demodulated data is discriminated by the signal power of a spread spectrum signal (PN 0). In this case, the signal PN 0 used in the preamble period from a time t1 to a time t2 of data to be transmitted is multiplexed even during transmission of data, and the power of the signal PN 0 during data transmission (from the time t2 to a time t3 ) is made smaller than that in the preamble period and is made larger than the power of the other data channels. |
