| 摘要 |
PURPOSE:To provide a communication system which quickly restores synchronism to keep the communication even in the case of a failure of reception of a preamble at the time of transmission start and to provide the transmission equipment used in this system. CONSTITUTION:A timing control circuit 14 connects switches 17 and 21 to terminals 17a and 21a for a prescribed time after the fall time of an oscillation output signal (b) and connects them to terminals 17b and 21b thereafter, and this switching is repeated synchronously with the oscillation output signal (b) having a certain period. When the modulation signal of the output modulated wave of a modulating circuit 18 is a synchronizing signal, a frequency conversion circuit 23 subjects a carrier to frequency hopping by a pattern based on the preamble code to output it to an output terminal 24. When the modulation signal of the output modulated wave of the modulating circuit 18 is data which is compressed by a memory circuit 13 with respect to time, the frequency conversion circuit 23 subjects the carrier to frequency hopping by a pattern based on a spreading code to output it to the output terminal 24. |
