ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / To use Ethernet is the most convenient way to set up a transportation network for a telemetry data acquirement system. However, due to its CSMA/CD (Carrier Sense Multiple Access and Collision Detection) mechanics, Ethernet cannot transport data synchronously. This paper analyzed important features of transportation in a distributed data acquirement system, and presents a resolve for synchronously transporting data in a distributed data acquirement system by using direct Ethernet connection and TDM (time division multiplexing) technique.

Ethernet is a common practice to reconstruct a networked telemetry system. However, Ethernet switch cannot best meet the requirement of data transportation in a telemetry system because of its asynchronous mode and the uncertainty of latency time. In addition, the temporal order of the telemetry data will be disrupted when using an Ethernet switch. A device similar to Ethernet switch is presented in this paper, which can transport data synchronously without losing the original temporal order of the telemetry data. Meantime, a special condition is arranged by the device that the timing signal could be transmit from the device to the receiver in a certain delay time, so a timing mechanism derived from IEEE 1588 PTP protocol could be adopted for high accuracy of timing and synchronous sampling control.

ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / Power supply is the most critical unit in an airplane. A defect in a power supply might lead to a crash. Therefore, it is very useful and important to monitor the status of the airplane's power supply during flight. This paper presents a real-time evaluation system constructed by a central process unit for processing and detecting defects and several remote units for acquiring parameters. Because of the huge amount of data acquired, a combination of Ethernet and time division multiplexing technique has been applied for constructing a 2.5Gbps synchronous data transportation network for the system.