無線通訊系統模組之研究與應用

Abstract

本論文中發表了一系列的無線通訊電路。首先，我們使用一套類比與數位 混合的模擬軟體來模擬一個在展頻系統中用來追蹝PN code的迴路。在迴 路的初始追蹤過程中，我們使用了一個有別於一般常用的 sliding correlator的方法，並且使用了一個charge pump的裝置來當作迴路濾波 器。模擬的結果顯示這個迴路確實能追蹤到PN code的相位並把資料解調 出來。其次，我們使用直接數位合成器與乘法器製作了一個快速的頻率合 成器。實際的測量結果顯示這個快速的頻率合成器約有 1%的相對頻寬而 可在238.95MHz和241.65MHz之間做跳頻。其頻率跳動的暫態時間是小於1 毫秒(usec)。最後，我們製作了一個可以在2.4到 2.4835GHz ISM(工業， 科學和醫學)頻段直接解調FSK信號的解調器，並且量測了這個電路的錯誤 率(BER)。實驗結果顯示錯誤率約在10e-5和 10e-4左右。 In this thesis, a number of wireless communication circuits are presented. First of all, a PN code tracking loop used in spread spectrum system is simulated by an analog/digital mixed mode software. An initial synchronization method that is diffe- rent from the commonly used sliding correlator is applied in the loop. The loop filter is realized by a charge pump device to convert the digital states to clearly specified voltage le- vels. Simulation results show this loop can correctly despread the PN code. Secondly, a fast frequency synthesizer(FFS) is realized based on direct digital synthesizer(DDS) and multi- pliers. The measurement results show that the FFS can hop in the range from 238.95MHz to 241.65MHz. The relative hopping band- width is about 1% and the settling time is less than 1 usec. Fianlly, a 2.4-2.4835GHz ISM(Industrial, Science, and Medical) band direct conversion FSK demodulator is presented. Measurement results show that it can demodulate RF band FSK signals directly to baseband datas. The bit error ratio(BER) of this circuit is also measured and turns out to be in the range around 10e-5- 10e-4.