www.pudn.com > FCC_UWB.rar > test_uwb.m

clc; 
clear; 
Ts=1e-7; 
smp = 1024;             % number of samples 
Tmin =-4e-9;           % lower time limit 
Tmax = 4e-9;            % upper time limit 
alpha=0.25e-9; 
alphastep=0.043e-9; 
dt = (Tmax - Tmin) / smp; % sampling period 
fs = 1 / dt; 
frequencysmoothingfactor=8; 
N=frequencysmoothingfactor*smp;  %N=8*1024=8192  
df=1/(N*dt);   
positivefrequency=linspace(0,(fs/2),N/2); 
t=linspace(Tmin,Tmax,smp);% initialization of the time axis 
emissionmask=cp0703_generate_mask(N,fs); 
for n=1:6; 
    a=alpha; 
    pulse1(1,:) = 48*2^(1/2)*(1/a)^(1/2)*pi^2/a^4*exp(-2*pi*t.^2/a^2)-... 
        384*2^(1/2)*(1/a)^(1/2)*pi^3/a^6*t.^2.*exp(-2*pi*t.^2/a^2)+... 
        256*2^(1/2)*(1/a)^(1/2)*pi^4*t.^4/a^8.*exp(-2*pi*t.^2/a^2); 
    pulse1(1,:)=pulse1(1,:)/max(abs(pulse1(1,:))); 
     
    X=fft(pulse1(1,:),N); 
    X=X/N; 
    E=fftshift(abs(X).^2/(df^2)); 
    Ess=2*E((N/2+1):N); 
    singlederivativePSD=10*log10((1/Ts)*Ess/377)+90; 
    figure(1); 
    plot(positivefrequency/1e6,emissionmask,'r','linewidth',[1]); 
    hold on 
    plot(positivefrequency/1e6,singlederivativePSD); 
    X=xlabel('Frequency [MHz]'); 
    set(X,'fontname','Arial','fontsize',10.5); 
    Y=ylabel('ESD [dBm/MHz]'); 
    set(Y,'fontname','Arial','fontsize',10.5); 
    axis([0 12e3 -120 0]); 
    
    text(4e3,-35,'FCC UWB indoor emission mask','fontname','Arial','fontsize',10.5); 
    text(4.3e3,-105,'\alphamax\rightarrow','fontname','Arial','fontsize',10.5); 
    text(10e3,-100,'\leftarrow\alphamin','fontname','Arial','fontsize',10.5); 
     
    alpha=alpha+alphastep; 
end 
 title('高斯函数的4阶导函数的ESD与\alpha的关系和FCC掩蔽的比较'); 
 grid