多重信號多工技術之數位信號處理實作

DSP Implementation of Multi-signals Multiplexing

林信標(Hsin-Piao Lin) ； 江彥良(Yan-Liang Chiang)

《臺北科技大學學報》 39卷2期 (2006/09) Pp. 23-33

https://doi.org/10.29768/JNTUT.200609.0003

摘要

本文章利用一種新的信號處理技術在不改變傳輸通道條件下，同時傳送多組信號。將此技術融入現行通訊系統中，有助提昇資料傳輸率。此信號處理技術首先探討如何找出正交弦式信號，傳送端利用這些正交弦式信號將輸入信號作編碼及混合。接收端並利用相對應的正交弦式信號將接收到的信號正確無誤的分離。在此部份利用軟體模擬方式驗證。再者，本文章將此信號處理技術架構在數位信號處理器(Digital Signal Processor, DSP)來實現一完整的通訊系統，並驗證系統的效能。過程中利用了delay and correlation演算法正確偵測出封包的起始位置，並以上升餘弦內插法解決因為傳送端與接收端取樣頻率不同所造成的時序誤差。接著從實際測試中，同時傳送兩組信號，驗證此系統在不增加傳輸通道條件下，確實能將傳送信號混合傳輸後，於接收端仍能正確無誤的分離，達到同時傳輸多組信號的目的，其正確解碼分離信號的正確率為98.22%。

關鍵字

正交編解碼 ； 數位信號處理器 ； 封包偵測 ； 時序回覆

並列摘要

In this paper, a novel signal process method was proposed for communication systems allowed multi-signals mixing in a narrowband. We introduced a way of finding the orthogonal sinusoids signals for encoding and decoding and verified by the software simulation.
After verification by simulation, we furthermore implement this novel signal process method on DSP board to prove the feasibility. Two DSP boards were used. One is transmitter, the other is receiver and data were transmitted over audio line. There will be a synchronization problem between transmitter and receiver. In order to solve the problems of synchronization, we separate it into two parts. 1.) To detect the start of packet by delay and correlate algorithm. 2.) To recover timing delay by raised cosine interpolation.
The implementation results shows that when two mixed signals are transmitted in the wired channel they could be separated in the receiver. The packet correct rate of the system could achieve 98.22%

並列關鍵字

Orthogonal Encode & Decode ； Digital Signal Processor ； Packet Detection ； Timing Recovery