- 學位論文
916.5 MHz 數位無線系統數據封包之韌體編碼與解碼
Firmware Encoding and Decoding in 916.5 MHz Digital RF Transceiving System
摘要
本論文之研究分別對無線數據封包（Wireless Data Packet）編碼、解碼之收發系統設計，以及將射頻收發器進行最佳化調整，使得整體無線系統效能提升，其中無線數據封包 (Wireless Data Packet) 之格式包含：前導碼（Preamble）、同步碼（Sync. Header）、資料欄位（Payload Data）、訊框檢查序列（Frame Check Sequence；FCS）、停止位元（Stop Bit）和防護時間（Guard Time）。 在非同步串列傳輸系統之操作模式中，系統接收端如何實現時脈與數據回復功能(Clock and Data Recovery；CDR)是非常關鍵的技術，在無線的通道中，干擾和雜訊是無可必免的，因此使用微控器作為數位訊號處理，使得系統具備抗干擾和抗雜音的能力。另外，也使用韌體的方式來實現CRC-8錯誤偵測機制，檢查資料位元於接收過程中有無發生錯誤，以避免產生錯誤而造成系統誤動作，對於資料的保密性有顧慮時，可以使用加密與解密技術將資料作轉換，以達到資料的安全性，這些內容在本文章節中將會一一討論。
並列摘要
This thesis investigates encoding / decoding techniques for transmission and reception of wireless data packets via 916.5 MHz RF transceivers. The format of the wireless data packet intended consists of various data fields, including preamble, synchronization header, payload, frame check sequence, stop bit, and guard time. In the universal asynchronous receive / transmit (UART) mode of operation, the ability of the receiver to accomplish clock and data recovery (CDR) is very critical to the system throughput performance. Since interference and noise over the air is ubiquitous, anti-interference signal transmission / reception is definitely very essential for a reliable digital wireless communication link. Digital signal processing (DSP) techniques via uC-based firmware are utilized to help enhance noise-robustness. Moreover, 8-bit CRC (cyclic redundancy check) frame checking sequence (FCS) is also embedded in the uC-based firmware in order to incorporate the capability of error detection and thus prevent from false data validation on the receive side. When data security is an indispensable concern, various encryption / decryption techniques with different secret keys can also be included for information securement.