以數位訊號處理器實現無線光通訊系統

A Free-Space Optical Communication System using Digital Signal Processors

王裕閔(Yu-Ming Wang)

指導教授 ： 江簡富

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.10140

摘要

無線光通訊具有易架設、高傳輸速度、不易竊聽、不需經過頻譜申請等優點。本論文設計一個光收發模組來展示無線光通訊的鏈結。光收發模組包含一個發射器以及一個接收器，發射器是由雷射驅動電路、Thorlabs 850 nm 10mW 的雷射光源以及對準器所組成，接收器是由GaAs PIN 感光二極體、轉阻放大器和取決電路所組成。在傳送端，數位訊號經由電腦的編碼再經由類比數位轉換器的轉換來調變雷射光源。在接收端，光訊號由GaAs PIN 感光二極體所接收再經由類比數位轉換器的處理以還原傳送資訊。
本論文提出一個修正的調變及編碼方式來改善傳輸效能。利用前置位元以及漢明碼來達成同步與錯誤更正以改善位元串的正確性以及可靠性。本論文使用德州儀器定點TMS320C6416T 的數位訊號處理器以及高速數位類比轉換器AED-101提供80 Msps 的取樣率。本論文以紅外線通訊協定為基礎，距離一公尺、資料發射率1.152 Mbps，展示一無線光通訊的觀念。

關鍵字

無線光通訊 ； 紅外線通訊協定 ； 數位訊號處理器 ； 及高速數位類比轉換器

並列摘要

There are several advantages with optical communications in free space such as high data rate, dedicated communication and being difficult to eavesdrop. Free-space optical communications is an alterative to short-distance communcations. In this work, optical transceiver modules are designed to demonstrate an optical communications link. An optical transceiver module consists of a tansmitter and a receiver. The transmitter is composed of a driver circuit
and a Thorlabs L850P010 850 nm 10 mW diode laser with a monitor-diode feedback loop and focused by an external collimation tube. The receiver is composed of a TMC-8D41-000
GaAs PIN plus pre-amplifier photodiode and decision circuits. Digital signals from PC are encoded and sent to a digital-to-analog converter (DAC) to modulate the diode laser. At the receiver side, the light is received by the GaAs PIN photodiode, then sent to an analog-todigital
converter (ADC) for post processing. We propose a revised protocol to improve the performance in the conventional encoding scheme. The revised protocol has the capability
of synchronization and error correction. The preamble code and Hamming encoding scheme are used to improve the accuracy and reliability of the bit stream. The TI TMS320C6416T fixed-point digital signal processor (DSK) with an analog expansion daughterboard (AED-101) are used to provide maximum sampling rate up to 80 Msps. In this work, IrDA data rate of 1.152 Mbps is chosen as a reference for a communications link over one meter.

並列關鍵字

Free space optics ； IrDA ； Digital signal processors ； AED-101

參考文獻

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