pcwina.m

此程序给出了不同情况的雷达距离测量仿真平台

% Pulse Compression Spectrum with Windows
% ---------------------------------------
% pcwina.m

clear;clf;clc;

% Input Chirp Bandwidth and Pulsewidth

bw=1e6;		% Bandwidth - Hz
T=1e-4;		% Pulse Width - sec

%Input FFT Points

lfft=1024;

% Set Time Base 

t=-T/2:T/(lfft-1):T/2;

% Sample Complex Chirp

s= exp(-j*pi*bw*t.*t/T);

% Window Sample Chirp

w1=1;                                      % Uniform Weighting					
w2=.54+.46*cos(2*pi*t/T);                  % Hamming Weighting
w3=.5*(1+cos(2*pi*t/T));                   % Hanning weighting
w4=.42+.5*cos(2*pi*t/T)+.08*cos(4*pi*t/T); % Blackman Weighting


sw1=s.*w1;sw2=s.*w2;sw3=s.*w3;sw4=s.*w4;

% Find Fourier Spectrum of Chirp

ZY1=fft(sw1,lfft);ZY2=fft(sw2,lfft);
ZY3=fft(sw3,lfft);ZY4=fft(sw4,lfft);
Y1=fftshift(ZY1);Y2=fftshift(ZY2);
Y3=fftshift(ZY3);Y4=fftshift(ZY4);

% Find Power Spectral Density

Psd1=Y1.*conj(Y1)/lfft;
Psd2=Y2.*conj(Y2)/lfft;
Psd3=Y3.*conj(Y3)/lfft;
Psd4=Y4.*conj(Y4)/lfft;

% Find Matched Filter Time Waveform

zh1=ifft(Psd1,lfft);zh2=ifft(Psd2,lfft);
zh3=ifft(Psd3,lfft);zh4=ifft(Psd4,lfft);

h1=fftshift(zh1);h2=fftshift(zh2);
h3=fftshift(zh3);h4=fftshift(zh4);

% Plot Log of Time Waveform

zz1=20*log10(abs(h1));
zz2=20*log10(abs(h2));
zz3=20*log10(abs(h3));
zz4=20*log10(abs(h4));

C1=max(zz1);C2=max(zz2);
C3=max(zz3);C4=max(zz4);

subplot(221);
plot(t,zz1-C1);grid;
axis([ -T/16 T/16 -40 0 ]);
title(['PC Matched Filter - Uniform']);
xlabel('Time - Sec');ylabel('Amplitude - DB');

subplot(222);
plot(t,zz2-C2);grid;
axis([ -T/16 T/16 -80 0 ]);
title(['PC Matched Filter - Hamming']);
xlabel('Time - sec');ylabel('Amplitude - dB'); 

subplot(223);
plot(t,zz3-C3);grid;
axis([ -T/16 T/16 -80 0 ]);
title(['PC Matched Filter - Hanning']);
xlabel('Time - sec');ylabel('Amplitude - dB'); 

subplot(224);
plot(t,zz4-C4);grid;
axis([ -T/16 T/16 -120 0 ]);
title(['PC Matched Filter - Blackman']);
xlabel('Time - sec');ylabel('Amplitude - dB');