adapt_ieee.m

一种改变自己模型适应IEEE标准模型的源码

clear;
S21String = 'S21_bb_ch1.mat'; 
S21 = importdata(S21String);            

% Set the carrier frequency to be the middle of band 2, 3960 MHz.

Fc=3960e6; 
Ls=length(S21);

% Define the sampling time
Ts = 3.125e-7/990;

% frequency points
step= 5e6;
fs = 1e9:step:13e9; 

% Netto frequency band [3.170 : 4.755] GHz

f_0=1e9; %simulation start frequency

f_l  = 2.375e9+0.530e9; f_h = 5.545e9-0.530e9; % %Brutto frequency Band width lowest and highst f 
f_bp= [f_l:step:f_h];

U_f= [((f_l -f_0)/step)+1:((f_h -f_0)/step)+1];
L_f=length(U_f);

H_bpBr = S21(U_f);
Wd = zeros(1,L_f);
W	= tukeywin(L_f, 0.5); 

H_bpNetto= W'.*H_bpBr ;

M  = length(H_bpNetto);    N= 4*M; % 4*M is the best resample rate nearly Ts 
df	= 5e6; R	= df*N;   dt	= 1/R; T	= N*dt;

f	= df*(0:N-1); t	= dt*(0:N-1);

tt	= (0:dt:300e-9);
it	= 1+round(mod(tt,T)/dt);
h_bp = ifft(H_bpNetto,N);

%--------------------------------------------
%--------------------------------------------
tt_co =tt(1: length(h_bp));
tt_sa = [0:500]*Ts; 
h_sa =interp1(tt_co,h_bp,tt_sa, 'linear');

%--------------------------------------------
% Translate the data from passband to baseband.
%--------------------------------------------

h_tp = h_sa.*exp(j*2*pi*Fc*[1:size(tt_sa)]*Ts);

%--------------------------------------------
% Truncate the start of the response to remove any delay introduced in the
% reinterpolation process.
%--------------------------------------------
Len = 500; %IEEE channel length
h_tp_my =zeros(Len,1); 
gd_start = find(abs(h_tp)==max(abs(h_tp)));
h_tp_shift = [h_tp(gd_start:end)'; zeros(gd_start-1,1)];  %remove any delay

% remove values smaller than 10^-5 of the maximum
gd_end = min(find(abs(h_tp_shift )<1e-4*max(abs(h_tp_shift)))); 
I=(1:gd_end);
h_tp_my (I) = real(h_tp_shift(I)); 

%-------------------------------------------
%The energy of the realization have to be normalized to unity
%-------------------------------------------
E= sum(abs(h_tp_my).^2); %the Energie of the time discret signal h_tp_my
h_tp_my =h_tp_my/sqrt(E);

%-------------------------------------------
%%% save continuous-time (time,value) pairs to files
%-------------------------------------------
SaveStr=sprintf('%s','h_bb_ch1'); 
% A complete self-contained file for Matlab users
save ([SaveStr '.mat'], 'h_tp_my') ;

%-------------------------------------------
%%% plots
%-------------------------------------------


figure(1) %S21(f)  magnitude
xaxis=' f_{} [GHz]'; yaxis='|S_{21}| [dB]';
hold on;
owntitle=('20log_{10}(S_{21} (f))'); 

xmin=2.8; xmax = 5.2;  xstep = 0.2; ymin= -110; ymax= -30;  ystep = 10;
hold on;
plot(f_bp/1e9, 20*log10(abs(H_bpNetto)),'--b','LineWidth',2);  
plot(f_bp/1e9,-40+20*log10(abs(W)),'--r', [Fc Fc]*1e-9,[ymin ymax], '-.k','LineWidth',2); hold off;
title(owntitle,'fontsize',12); xlabel(xaxis,'fontsize',12);
set(gca,'XTick',xmin:xstep:xmax);  ylabel(yaxis,'fontsize',12); set(gca,'YTick',ymin:ystep:ymax); 
xlim([xmin xmax]); ylim([ymin ymax]); 
legend ('transfer function', 'used  window (normalized)')
hold off; grid on

%-------------------------------------------
% %%   time continius impulse response 
%-------------------------------------------

figure(2)
xaxis=' t_{} [ns]'; yaxis='|h_{21}(t)| [dB]';
xmin=5; xmax=80;  xstep=5; ymin=-130; ymax= -60;  ystep =10;
hold on; plot(tt*1e9,20*log10(abs(h_bp(it))),'b-','LineWidth',1);...
    plot(tt_sa*1e9,20*log10(abs(h_sa)),'r-','LineWidth',1); hold off;
xlabel(xaxis,'fontsize',12);set(gca,'XTick',xmin:xstep:xmax);   
ylabel(yaxis,'fontsize',12); set(gca,'YTick',ymin:ystep:ymax);  
xlim([xmin xmax]);ylim([ymin ymax]); 
grid on;
shg

%-------------------------------------------
%-------------------------------------------

figure(3)
xaxis=' t_{} [ns]'; yaxis='|h_{tp}(t)| [dB]';
xmin=-5; xmax=60;  xstep=5; ymin=-1; ymax= 1;  ystep =0.1;
plot(tt_sa(1:500)*1e9, h_tp_my(1:500),[gd_end gd_end]*Ts/1e-9,[-0.5 0.5],'r--','LineWidth',1.5);
xlabel(xaxis,'fontsize',12);set(gca,'XTick',xmin:xstep:xmax);   
ylabel(yaxis,'fontsize',12); set(gca,'YTick',ymin:ystep:ymax);  
xlim([xmin xmax]);ylim([ymin ymax]); 
grid on;

%--------------------------------------------
%--------------------------------------------