% Matlab 程式設計 基礎篇，葉倍宏 編著，全華
% Matlab 程式設計 應用篇，葉倍宏 編著，全華
% 以下程式摘自以上書籍，敬請多多選購。 (書中含大量實用範例)
% BJT Network (frequency response): 淹沒CE amp.
%input
    clear;
    vcc=20;
    rs = 1000;      r1 = 40000;     r2 = 10000;
    rc = 4000;      re = 2000;      rl = 2200;
                c1 = 10;
                    c1 = c1*10^-6;
                c2 = 1;
                    c2 = c2*10^-6;
        beta = 100;                % beta value
            cbe = 20;
                cbe=cbe*10^-12;
            cbc = 3;
                cbc=cbc*10^-12;
            cce = 5;
                cce=cce*10^-12;
% r'e
        vth = vcc*r2/(r1+r2);
        rth = parl2(r1,r2);
            IE = (vth-0.7)/(re+rth/(beta+1));
            rep = 25/(IE*1000);
%
            f = logspace(-1,9);
                zc1 = 1./(j*2*pi*f.*c1);
                zc2 = 1./(j*2*pi*f.*c2);
% input impedence
            zinb = beta*(rep+re);
            zin = parl2(rth,zinb);
% bjt:gain
                A = -rc./(rep+re);
                    rcl = parl2(rc,rl);
                    Av = -rcl./(rep+re);
% miller theory
            cinm = cbc*(1-Av);
            cin = cinm+cbe;
                coutm = cbc*(1-Av)/-Av;
                cout = coutm+cce;
% output impedence
            zout = rc;
% cutoff frequency
            fc1 = 1./(2*pi*(rs+zin)*c1);
            fc2 = 1/(2*pi*(zout+rl)*c2);
            if fc1>fc2
                fc = fc1;
            else
                fc = fc2;
            end
% cal
        atl1 = zin./(rs+zc1+zin);     % low f part
            atl3 = rl./(zout+zc2+rl);
                atl = atl1.*A.*atl3;
                    atpl = 20*log10(abs(atl)); 
            rszin = parl2(rs,zin);    % high f part
            zoutrl = parl2(zout,rl);
                zcin = 1./(j*2*pi*f.*cin);
                    zcout = 1./(j*2*pi*f.*cout);
            ath1 = zcin./(rszin+zcin);
            ath3 = zcout./(zoutrl+zcout);
                ath = ath1.*ath3;
                    atph = 20*log10(abs(ath)); 
            atp = atpl+atph;      % combination  
% plotting 頻率-增益圖 以及  頻率-相位圖
    close;
subplot(2,1,1);
    semilogx(f,atp,'r-');       
    grid on;
    axis([1.0e-1 1.0e9 -100 0]);
    xlabel('f (Hz)');       ylabel('At (dB)');
subplot(212);
    semilogx(f,(angle(atl)+angle(ath)).*57.3,'g-');    
    grid on;
    xlabel('f (Hz)');            ylabel('angle');
    axis([1.0e-1 1.0e9 -360 0]);