rfid應用開發(fā)實務簡介-資料下載頁
2025-09-30 14:55本頁面
【正文】 r all tags with a serial number that starts with 01 to respond, and then 010. This is called walking a binary tree, or tree walking. (See singulation.) RFID 應用開發(fā)實務導論 2022/10/23 45 TTFTag talks first ? A means by which a reader in a passive UHF system identifies tags in the field. When tags enter the reader39。s field, they immediately municate their presence by reflecting back a signal. This is useful when you want to know everything that is passing a reader, such as when items are moving quickly on a conveyor. In other cases, the reader wants to simply find specific tags in a field, in which case it wants to broadcast a signal and have only certain tags respond. RFID 應用開發(fā)實務導論 2022/10/23 46 Singulation ? A means by which an RFID reader identifies a tag with a specific serial number from a number of tags in its field. There are different methods of singulation, but the most mon is tree walking, which involves asking all tags with a serial number that starts with either a 1 or 0 to respond. If more than one responds, the reader might ask for all tags with a serial number that starts with 01 to respond, and then 010. It keeps doing this until it finds the tag it is looking for. RFID 應用開發(fā)實務導論 2022/10/23 47 Active Tag ? A . patent for the anticollision features of its eLink wireless munication protocol. When several RFID tags are in the field of a single reader, their signals interfere with one another, confusing the reader. Most anticollision protocols require active, or batterypowered, tags to remain awake while they municate with the reader until all their serial numbers are read. RFID 應用開發(fā)實務導論 2022/10/23 48 Active Tag (續(xù) ) ? To conserve battery life, this came up with a protocol that doesn39。t require all tags to remain awake. The reader sends out a signal that wakes up the tags and asks them to transmit the first bit of their serial number. The reader signals all the tags that don39。t send back a one to go back to sleep until later. The reader keeps eliminating tags until it finds the one with the highest serial number. Then, it wakes up the other tags and goes through the process again. This happens so quickly that it appears as though the tags are being read simultaneously. The protocol works on up to 16 million tags. RFID 應用開發(fā)實務導論 2022/10/23 49 RFID 應用系統(tǒng)架構(gòu)及功能 ? 系統(tǒng)架構(gòu)及功能說明 標籤 讀取器 天線 中介軟體 應用系統(tǒng) 標籤資訊 無線電波 標籤微波信號 資料封包 標籤編碼 系統(tǒng)架構(gòu)與功能流程 RFID 應用開發(fā)實務導論 2022/10/23 50 RFID的研究可區(qū)分成三大類 ? 第一類主要在於 RFID硬體的研發(fā)：其目的在於降低成本（尤其標籤價格）、克服環(huán)境影響增加通信距離 ? 第二類則致力於中介軟體 (Middleware)的開發(fā)：中介軟體扮演讀取器解碼所得標籤相關資訊與後續(xù)應用系統(tǒng)的溝通橋樑 ? 最後一類就是 RFID技術(shù)於產(chǎn)業(yè)應用系統(tǒng)開發(fā)：目前國內(nèi)政府方面有經(jīng)濟部與工研院合作，推廣 RFID資訊與市場應用 RFID 應用開發(fā)實務導論 2022/10/23 51 RFID 應用開發(fā)實務導論 2022/10/23 52 圖片，資料來源係引用 ? 帝商科技 ? EPCglobal Taiwan ? EPCglobal Home
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