A Novel High-Precision Synchronous Sampling Mechanism for Distributed Test System Based on Optical Fiber Network and Low-Cost Field-Programmable Gate Array

Abstract

In this paper, we propose a distributed test system based on optical fiber network with multiple devices. In order to resolve the data sampling synchronicity problems, a novel synchronous sampling mechanism is developed to achieve high-precision sampling synchronicity among data acquisition devices with relatively low-cost hardware. First, we present the design of the system based on optical fiber network and the mechanism implemented in Field-Programmable Gate Array (FPGA) devices. Then, the device clocks are calibrated to run on a same frequency using a clock-disciplining algorithm for hardware implementation. In addition, propagation delays, which are used for the synchronous errors compensation during data analysis, are precisely measured using a high-precision time interval measurement approach based on delay-chain loop comparison method. A series of experiments on a real test system demonstrate the effectiveness of the proposed models and methods, and the mechanism has been employed in a general-purpose reprogrammable device cyclone-II (Altera).