低成本集成解決方案使新的NFC無線應用程序

　　近場通信（NFC）技術已開始大舉進軍移動通信產(chǎn)品，如手機，和許多其他應用，包括智能卡、銷售點終端、公共交通支付卡、自動售貨機、訂票、智能廣告海報，和更多。為了滿足無線NFC解決方案無處不在所需的成本/價格點，半導體供應商和系統(tǒng)設計組織正在制定更高度集成的解決方案，降低系統(tǒng)成本并簡化系統(tǒng)實現(xiàn)。

　　無線通信有多種選擇，每個節(jié)點之間有不同的數(shù)據(jù)吞吐量范圍和物理距離限制，如圖1所示。有些無線標準在某些方面是重疊的，有些將具有相同的范圍或數(shù)據(jù)吞吐量，所以最終應用程序?qū)⒃跊Q定哪個標準最適合系統(tǒng)中起著重要作用。

　　Figure 1： Many wireless standards are available for designers to use in their system. For very-short range communications， the NFC wireless standard can operate at distances of less than 20 cm， vs. other standards that function over much larger distances. （Image courtesy of the NFC Forum.）

　　NFC is a form of RFID， but it has its own set of standards that govern its interface and operation. Vendors that design products to meet the standards will be able to link their products to and interoperate with any other NFC-enabled products. The NFC standards determine not only the contactless operating environment， but also the data formats and data transfer rates.1

　　However， before delving into the design of NFC systems， we will review some of the basics of NFC operation. The NFC standard defines a short-range wireless connectivity capability that can carry secure two-way interactions between electronic devices. A simple communications link between two NFC devices is easy to establish and does not require any setup by users. Once established the NFC link allows users to access digital content， perform contactless transactions， and even connect electronic devices by placing devices close to each other.