空間光通信技術具有簡單、方便、傳輸速率高及設計容易等優點，因提供短程通信上另一項選擇。本研究為製作空間光發射/接收機，以傳輸讈音信號為目的，首先，將語音信號進行類比數位轉換(A/D)，再進行編碼，編碼過程包括將並列資料轉換成串列，並在資料前後加入起始、停止位元，而後以PCM編碼方式透過紅光雷射在空間中傳輸。在接收端，首先進行解碼，包括串並轉換而後取得起始、停止位元，跟發射機取得同步，以取得到正確資料傳送，再將並列資料，透過數位-類比轉換器(D/A)，將語音信號還原。目前研究成果已完成發射/接收機之製作，以語音為信號源，發射機資料傳輸率為200kbit/s，光發射功率15mW，傳輸距離50m以上。

There are several advantages for optical communication in free space such as simplification,convenience, high bit rate,and sasy design,Free-space optical communication is an alternative for short distance communication. In this work, we desighn and fabricate the optical transmitter and receiver for delivery of audio signal in free-space communication. In circuit design section, audio signals proceed to analog to digital conversion (A/D)and then encode the data. The procedures of encoding block include parallel-series conversion, data cell process adding starter and stop bit, thereby modulate the laser by PCM format in free space. Data cell at receiver terminal will be decoded exactly and synchronized with transmitter terminal for data transmission. After digital to analog conversion, parallel-series data will decode to audio signals. We have accomplished the circuit design of optical transmitter and receiver for transmission of audio signals. Transmission bit rate, optical output power, and transmission distance at transmitter terminal are 200kbit/s,15mW,and >50m, respectively.

第一章 緒論
第二章 空間光發射/接收機設計原理
第三章 空間光發射/接收機實作與量測
第四章 結論

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