以FPGA 設計及實現GFSK 調變器

FPGA-BASED DESIGN AND IMPLEMENTATION OF GFSK MODULATOR

葉怡初(Yeh yi chu)

指導教授 ： 劉皆成

大同大學/電機資訊學院/通訊工程研究所/碩士(2007年)

摘要

由於GFSK與FSK的調變原理相似，唯一差別為GFSK是在FSK調變器之前加入一個高斯濾波器 (Gaussian Filter)，其最大頻率偏移量與傳送位元的速率都跟調變器的調變指數有關，也就是說，若其調變器的調變指數(Modulation Index)為0.5，其最大頻率偏移正好為傳送位元速率的一半，而高斯頻率鍵移(Gaussian Frequency Shift-Keying)調變方式因為擁有窄小的頻寬、好的雜訊免疫力及固定的封包，所以一些通訊系統諸如藍芽，Skypephone和低功耗數字接收器等)都使用它為其調變方式。在本篇論文中，一開始我們著重於GFSK調變原理的介紹，接著以藍芽系統中的GFSK調變為基礎，利用FPGA技術，分別完成每個小單元，諸如NRZ轉換器，高斯低通濾波器，累加器，正/餘弦的函數對應器，數位式複數混頻器，最後再將各個小單元整合，並且一步步來實現GFSK調制器的整體架構。

關鍵字

設計及實現調變器

並列摘要

GFSK modulation is similar with FSK, the only different thing of them is added a Gaussian filter before a FSK modulator, the modulation index of modulator is in relation to maximum frequency deviation and data rate. In another way, if the modulation index of modulator is to 0.5, then the maximum frequency deviation is exactly the half time of data rate. The GFSK (Gaussian Frequency Shift Keying) modulation has some of benefits, like narrower bandwidth, good noise immunity, constant envelope etc. As it modulation scheme, some wireless systems such as Bluetooth, Skypephone and Low-Power Highly Digitized Receiver are all application of GFSK scheme. In this thesis, we will first introduce the fundamental of GFSK modulation, and refer to GFSK modulator of Bluetooth, then step-by-step complete the basic blocks by using FPGA, such as a NRZ converter, Gaussian low pass filter, 8-bits accumulator, SINE/COSINE LUTs, Digital complex mixer. After those blocks complete, I integrate those blocks to accomplish the implementation of GFSK modulator.

並列關鍵字

DESIGN AND IMPLEMENTATION

參考文獻

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