Radar loop and phase noise spec determination

Hello all,

I would like to generate a basic radar loop (Transmit bw=400Mhz, f center=9.5Ghz) and downconvert it back to IF (750Mhz) with a matlab code but I cannot. Below is the matlab code for it, can anyone help?

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clear all
close all
clc

c=3e8;
fs=20e9;
fc=9.5e9;
pw=12.5e-6;
prf=8e3;
bw=400e6;
R=1500;
t=0:1/fs:pw-1/fs;
k=bw/pw;
IF=750e6;

tx=(exp(-1i*(fc-bw/2+k.*t).*t));
TX=abs(fft(tx));
mf=fliplr(exp(1i*(k.*t).*t));
tx_pulse=[tx zeros(1,fs/prf-pw*fs)];
TX_PULSE=abs(fft(tx_pulse));
rx_pulse=circshift(tx_pulse,[1,round(2*R/c*fs)]);
L=length(rx_pulse);
TIME=1/fs:1/fs:L/fs;
down=exp(1i*(fc).*TIME);
DOWN=abs(fft(down));
rx_down=rx_pulse.*down;
RX_DOWN=abs(fft(rx_down));

subplot(311)
plot(TX_PULSE(end/2:end))

subplot(312)
plot(DOWN(end/2:end))

subplot(313)
plot(RX_DOWN(end/2:end))

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