Research On The Architecture Of Unified Time System For The Instrument On Network (ION)

Due to the absence of open architecture and information integrity in traditional instrument, the remote measurement, control and distribute test cannot be realized. At the same time, the open interconnect and sharing of the instrument resource cannot be carried out, and the test information cannot be transferred and used. That is, there exists the universally problem of the instrument technology for the application in wide area.Basing on the viewpoint of measurement information integrity and the principle of the open architecture, this paper puts forward the Instrument on Network (ION) that having the function of open interconnection and the ability of information integrity supporting, expounds the open architecture and technology element of it, and analyses the unified time problem and key technology of ION in depth. The main work is organized as follows:1. To solving the problem of open interconnection of instrument in wide area, an open architecture of ION is designed. The ION constructed logically by access layer, transmission layer and fabric layer, including test probe, measure-control HUB and measure-control server three kinds device units. The basic definitions and connotations are expounded in this paper in depth.2. To achieving unified time over the ION, the author brings forward a unified time system, and sets forth time transmission link and the architecture of unified time system based on it in this paper. As well as, the unified time system is researched from time source, time transfer and timekeeping, time regenerating and application, as follows:(1) The time source is researched from these aspects of structure model, judge rule and construction, and the hierarchy of it is introduced for the ION. As the first grade of time source, the technology characteristic of GPS class time source is analyzed. Also, as a kind of second grade time source, one time source based on the CDMA system is put forward. The result of experimentation shows that time synchronization accuracy within several microseconds is achieved.(2) The time transmission and timekeeping technology is researched from time port, time transmission link, clock calibration and time forecast. To decreasing transmission delay error caused by relative frequency deviation in time port clock, a relative frequency deviation method based on unitary time interval deviation series is designed and simulated in this paper.(3)The time regeneration and application technology is studied, and the concept and model of the Time Service Unit (TSU) is researched. In order to synchronously gather information on multi-probes, process test data with multi-frequencies, and realize the standardization of sample clock in probe, a method that generating synchronous sample clock is designed, and synchronization resample technology based unified time is studied.(4) To realize time synchronization over Ethernet, a synchronized medium access controller (SMAC) is set forth. The SMAC has the functions of time transmission, time detection and clock regeneration. Also, an open loop time transmission method based on this SMAC is designed. The result of experimentation shows that time transfer accuracy within 25 nanoseconds is achieved through one SMAC switcher.