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【MATLAB】帶限基帶傳輸系統的模擬

        用Matlab通訊工具箱提供的rcosine函式作出一組滾升餘弦濾波器的衝激響應,滾降係數為0,0.5,0.75和1,並通過FFT求出其幅頻特性。碼元時隙為1ms,在一個碼元時隙內取樣10次,濾波器延時為5個碼元時隙。 程式如下:
clc;
Fd = 1e3;
Fs = Fd * 10;
delay = 5;
for r = [0,0.5,0.75,1]
    num = rcosine(Fd,Fs,'fir/normal',r,delay);
    t = 0 : 1 / Fs : 1 / Fs * (length(num) - 1);
    figure(1);
    plot(t,num);
    axis([0 0.01 -0.2 1.1])
    hold on;
    Hw = abs(fft(num,1000));
    f = (1 : Fs / 1000 : Fs) - 1;
    figure(2);
    plot(f,Hw);
    axis([0 1500 0 12]);
    hold on;
end
如圖: