Design And Optimization Of High-speed Wireless Data Acquisition Terminal

Data acquisition system (DAS) has been widely used in many fields such as enginediagnosis, safeguard applications, power quality analysis and so on. Most of the DASstransmit data by wired network. For example, CAN, Modbus and so on. They are highcost and not flexible enough. Using wireless solutions reduces data acquisition cost andpermits easy expansion for measurement points. It allows connection to the point that isphysically or economically difficult to access. Thus, wireless data acquisition system(WDAS) is desirable.This thesis first introduced the development of data acquisition system and thecurrent research status of wireless network, and made a detail research and discussion inthe feasures and application of wireless data acquisition terminal. The advantages and thedisadvantages of the existing wired data acquisition have been analysis. The combinationof wireless technology and data acquisition is a trend of development. Secondly, Zigbeeand GPRS protocol do not suit for those applications which require large bandwidthconsidering the low speed of them. This thesis designed a wireless data acquisitionterminal based on IEEE802.11n protocol. This terminal has six data acquisition channeland have a good performance in multipoint data acquisition. This thesis gave a detailintroduction of the hardware design. As for the software design, it gave the system’sconfiguration and the driver design of wireless design. In order to analyze informationprecisely at a distribution system in some fields such as power quality analysis, safeguardapplication, the WDAS is required to be able to synchronously measure the signals at eachpoint. So GPS is used to be the main synchronizing source which provides a accuratesampling clock on the WDATs. In this paper, to simplify the synchronous method and thedata packet structure, we present an optimal synchronous solution to realize precisesynchronization. In this solution a compact coding format for time information is usedinstead of the universal coordinate time (UTC) time information. Moreover, the consoleaided control method is adopted to realize the synchronization of all the WDATs. In thelast, considering the large quantities of sampled data and the limited bandwidth of the WDAT, the data compression algorithm is necessary. If data process is complex, it will bea hard load of the main MCU, and even cause the software system crash. Consideringthese factors, we employed the adaptive frequency and amplitude (AFA) algorithm due tothe non-optimized sampling frequency and sampled data bits. three experimentsdemonstrate that this method has a low complexity and is suitable for the embededplatform.