matlab_基于Costas编码的跳频信号的互相关时延估计

%% autocorrelation mathod % tone burst signal, freq hopped signal % used for range estimation %% initialization close all clear %% Signals parameters F=25*1000; %Signal freq A=1; %Amplitude Fs=400*1000; %Sample freq N=2048; %Samples Ts=N/Fs; %Sample time t=(0:N-1)/Fs; %Sample time %% Input signals Tsi=2/1000; %Signal time delay=2/1000; Ns=Tsi*Fs; %Signal samples Nd=delay*Fs; x=zeros(1,N); y=zeros(1,N); %% tone burst signals % ts=(1:Ns+1)/Fs; %Signal time % x(Nd:Nd+Ns)=A*sin(2*pi*F*ts); % y(1:1+Ns)=A*sin(2*pi*F*ts); %% Freq hopped signals sc=[1 3 9 10 13 5 15 11 16 14 8 7 4 12 2 6]; %Costas freq code series B=7*1000; %Bandwidth Nc=16; %Number of chips ts=(0:Ns-1)/Fs; %Signal time Fcf=F-B/2; %Freq of first chip dFc=B/(Nc-1); %d freq of chip for i=1:Ns x(Nd+i)=A*sin(2*pi*(Fcf+dFc*(sc(ceil(i*Nc/Ns))-1))*ts(i)); end y(1:1+Ns)=x(Nd:Nd+Ns); %% noise rng(1) n=randn(1,N); %x=x+n; SNR=10*log10(mean(x.^2)/mean(n.^2)); %Signal/noise %% xcorr c=xcorr(x,y,'coeff'); %互相关函数 c=c(N:2*N-1); %overthrow error points %% Display figure(10) plot(t,x) figure(20) plot(t,y) figure(30) plot(t,c)