npt = 8184;  % multiple of 132,
% to give an integer number of DAC waveform periods for the FFT
pmax = (16384*npt)^2;
nf = 396;  % number of data files
set1 = zeros(npt,nf);
set2 = set1;
for fx = [1:396]
  a=load(sprintf('raw_%3.3d.dat',fx));
  y1=a(1:npt,1);  set1(:,fx) = fft(y1);
  y2=a(1:npt,2);  set2(:,fx) = fft(y2);
end

f = [0:npt-1]';
sxx = mean(abs(set1).^2,2);
syy = mean(abs(set2).^2,2);
syx = mean(set2.*conj(set1),2);
dif = sxx + syy - 2*abs(syx);
plot(f, 10*log10(abs(syx)/pmax), f, 10*log10(dif/pmax))
legend('DAC + upconverter','downconverter + ADC')
xlim([0 npt/2])
dens_offset = 10*log10(1320e6/14/npt)
ylabel(sprintf('dBFS (subtract %.1f to get dBFS/Hz)',dens_offset))
xlabel('FFT bin (0 to 47.1 MHz IF, 1320 to 1272.9 MHz RF)')