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结合笔者研制的一种时分多址(TDMA)一点对多点通信系统,讨论了时分多址系统的位同步、帧同步、复帧同步和网同步。位同步实质是系统主时钟的提取,它通过在帧结构中设置前置码及后续信息扰码,由硬件完成;帧同步是在软件配合下,由硬件对未经扰码的独特码进行正确检测所得示位脉冲完成的;复帧同步是通过在下行帧中设置计数器,在软、硬件配合下实现的;网同步的过程就是系统定时和延时调整过程,它在软、硬件的配合下以用户站接收定时为基准,延迟发送时刻,使各用户站与中心站之间具有相同的等效半径,以期与中心站发送定时同步。时延调整是经人工粗调和自动细调两步完成的。
A bit-to-multipoint (TDMA) point-to-multipoint communication system developed by the author is discussed. Bit synchronization, frame synchronization, multi-frame synchronization and network synchronization are discussed. The essence of bit synchronization is the extraction of the master clock of the system, which is completed by the hardware by setting the preamble and the subsequent information scrambling code in the frame structure. The frame synchronization is performed by the software in a correct manner by the hardware for the unscrambled unique code Detection of the resulting bit pulse is completed; multi-frame synchronization is set by the downstream frame counter, with the cooperation of hardware and software to achieve; network synchronization process is the system timing and delay adjustment process, which in the hardware and software with Based on the reception timing of the user station, the transmission time is delayed, so that each user station and the central station have the same equivalent radius, so as to synchronize with the central station for sending the timing. Delay adjustment is done manually and coarsely and finely in two steps.