%程序用于繪制高斯及其各階導(dǎo)數(shù)脈沖、脈沖串的時(shí)、頻譜圖
clc;
clear all;
PlusTime=1;   %脈沖時(shí)間ns
PlusType=0;   %脈沖類型0:gaus；1:高斯1階導(dǎo)；2:高斯2階導(dǎo);5高斯5階導(dǎo)
PlusSamples=32; %單脈沖抽樣次數(shù)

pl=gausplus(PlusSamples,PlusType);
Pn=[1,0,0,0]';  %繪制單脈沖
% Pn=2*randint(16,1)-1;  %DSC_UWB的PN序列
% Pn=[0,0,0,0,1,0,0,0,...           %TH_UWB的PN序列
%     0,1,0,0,0,0,0,0,...
%     0,0,0,0,0,0,1,0,...
%     0,0,0,0,0,0,0,1,...
%     0,0,1,0,0,0,0,0]';

C=pl*Pn';   Tx=C(:);

     y=Tx;  TimeRatio=PlusTime/PlusSamples;  %5/7;
     y=y/max(y);  subplot(121);   grid;  plot((1:length(y))*TimeRatio,y,'r-'); xlabel('t(ns)'); legend('時(shí)城波形',0); grid on;
     %求y其相應(yīng)的fft變換,劃圖頻譜時(shí)將幅度取絕對值
     MaxSample=2^nextpow2(length(Tx));  MaxTime=MaxSample*TimeRatio;  fmin=1/MaxTime;
     yfft=fft(y,MaxSample); yfabs=abs(yfft);
     %變換yfabs頻率開始是0頻,而下標(biāo)從1開始,遞增fmin
     fend=6;  %需要劃到的最高頻  
     idx=1:floor(fend/fmin); freq=idx*fmin; subplot(122); 
     semilogy(freq,yfabs(idx)./max(yfabs),'b-')  
%      plot(freq,20*log(yfabs(idx)./max(yfabs)),'b-')  
% %      plot(freq,yfabs(idx),'y-')  
%      plot(freq,yfabs(idx)/max(yfabs),'r-'); xlabel('f(GHz)');legend('頻域波形',0);