• An Application of Sync Time Division Multiplexing in Telemetry System

      Lu, Chun; Yan, Yihong; Song, Jian; Beijing Zoweetech Ltd.; China Flight Test Establishment (International Foundation for Telemetering, 2013-10)
      High speed real-time data transportation is most important for telemetry systems, especially for large-scale distributed systems. This paper introduces a STDM (Sync Time Division Multiplexing) network structure for data transportation between devices in telemetry systems. The data in these systems is transported through virtual channels between devices. In addition, a proper frame format is designed based on PCM format to meet the needs of synchronization and real-time transportation in large-scale distributed telemetry systems.
    • A New Approach to Time Sync for Telemetry System

      Lu, Chun; Kung, Changchun; Song, Jian; Beinjing Zoweetech Ltd. (International Foundation for Telemetering, 2013-10)
      Instead of using a single data acquisition device, the distribute data acquisition system is broadly applied for onboard flight testing now. Therefore, the sync of data acquisition in varied devices and the real time data transportation have become the most important factors in a telemetry system. This paper presents a new approach to clock synchronization in a real time transportation network for a data acquisition system by using IRIG time code and an inner timer through network time recovery technique. This paper also illustrates how to keep the synchronization and continuity of a time tag used by each device through a precise estimation method for the difference of time resources and local inner timers.